Commit graph

264 commits

Author SHA1 Message Date
Amerigo Wang
c5f41752fd notifiers: sys: move reboot notifiers into reboot.h
It is not necessary to share the same notifier.h.

This patch already moves register_reboot_notifier() and
unregister_reboot_notifier() from kernel/notifier.c to kernel/sys.c.

[amwang@redhat.com: make allyesconfig succeed on ppc64]
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:14 -07:00
Linus Torvalds
39ab05c8e0 Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (44 commits)
  debugfs: Silence DEBUG_STRICT_USER_COPY_CHECKS=y warning
  sysfs: remove "last sysfs file:" line from the oops messages
  drivers/base/memory.c: fix warning due to "memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION"
  memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION
  SYSFS: Fix erroneous comments for sysfs_update_group().
  driver core: remove the driver-model structures from the documentation
  driver core: Add the device driver-model structures to kerneldoc
  Translated Documentation/email-clients.txt
  RAW driver: Remove call to kobject_put().
  reboot: disable usermodehelper to prevent fs access
  efivars: prevent oops on unload when efi is not enabled
  Allow setting of number of raw devices as a module parameter
  Introduce CONFIG_GOOGLE_FIRMWARE
  driver: Google Memory Console
  driver: Google EFI SMI
  x86: Better comments for get_bios_ebda()
  x86: get_bios_ebda_length()
  misc: fix ti-st build issues
  params.c: Use new strtobool function to process boolean inputs
  debugfs: move to new strtobool
  ...

Fix up trivial conflicts in fs/debugfs/file.c due to the same patch
being applied twice, and an unrelated cleanup nearby.
2011-05-19 18:24:11 -07:00
Rafael J. Wysocki
2e711c04db PM: Remove sysdev suspend, resume and shutdown operations
Since suspend, resume and shutdown operations in struct sysdev_class
and struct sysdev_driver are not used any more, remove them.  Also
drop sysdev_suspend(), sysdev_resume() and sysdev_shutdown() used
for executing those operations and modify all of their users
accordingly.  This reduces kernel code size quite a bit and reduces
its complexity.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-11 21:37:15 +02:00
Kay Sievers
b50fa7c807 reboot: disable usermodehelper to prevent fs access
In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it
should be on every system, the kernel forks processes during
shutdown, which try to access the rootfs, even when the
binary does not exist. It causes exceptions and long delays in
the disk driver, which gets read requests at the time it tries
to shut down the disk.

This patch disables all kernel-forked processes during reboot to
allow a clean poweroff.

Cc: Tejun Heo <htejun@gmail.com>
Tested-By: Anton Guda <atu@dmeti.dp.ua>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-06 17:52:32 -07:00
Serge E. Hallyn
fc832ad364 userns: user namespaces: convert all capable checks in kernel/sys.c
This allows setuid/setgid in containers.  It also fixes some corner cases
where kernel logic foregoes capability checks when uids are equivalent.
The latter will need to be done throughout the whole kernel.

Changelog:
	Jan 11: Use nsown_capable() as suggested by Bastian Blank.
	Jan 11: Fix logic errors in uid checks pointed out by Bastian.
	Feb 15: allow prlimit to current (was regression in previous version)
	Feb 23: remove debugging printks, uninline set_one_prio_perm and
		make it bool, and document its return value.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:47:06 -07:00
Serge E. Hallyn
bb96a6f50b userns: allow sethostname in a container
Changelog:
	Feb 23: let clone_uts_ns() handle setting uts->user_ns
		To do so we need to pass in the task_struct who'll
		get the utsname, so we can get its user_ns.
	Feb 23: As per Oleg's coment, just pass in tsk, instead of two
		of its members.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:47:03 -07:00
Rafael J. Wysocki
40dc166cb5 PM / Core: Introduce struct syscore_ops for core subsystems PM
Some subsystems need to carry out suspend/resume and shutdown
operations with one CPU on-line and interrupts disabled.  The only
way to register such operations is to define a sysdev class and
a sysdev specifically for this purpose which is cumbersome and
inefficient.  Moreover, the arguments taken by sysdev suspend,
resume and shutdown callbacks are practically never necessary.

For this reason, introduce a simpler interface allowing subsystems
to register operations to be executed very late during system suspend
and shutdown and very early during resume in the form of
strcut syscore_ops objects.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-15 00:43:46 +01:00
Kacper Kornet
aa5bd67dcf Fix prlimit64 for suid/sgid processes
Since check_prlimit_permission always fails in the case of SUID/GUID
processes, such processes are not able to read or set their own limits.
This commit changes this by assuming that process can always read/change
its own limits.

Signed-off-by: Kacper Kornet <kornet@camk.edu.pl>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-31 13:01:27 +10:00
Seiji Aguchi
04c6862c05 kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths
We need to know the reason why system rebooted in support service.
However, we can't inform our customers of the reason because final
messages are lost on current Linux kernel.

This patch improves the situation above because the final messages are
saved by adding kmsg_dump() to reboot, halt, poweroff and
emergency_restart path.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Reviewed-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:07 -08:00
Mike Galbraith
5091faa449 sched: Add 'autogroup' scheduling feature: automated per session task groups
A recurring complaint from CFS users is that parallel kbuild has
a negative impact on desktop interactivity.  This patch
implements an idea from Linus, to automatically create task
groups.  Currently, only per session autogroups are implemented,
but the patch leaves the way open for enhancement.

Implementation: each task's signal struct contains an inherited
pointer to a refcounted autogroup struct containing a task group
pointer, the default for all tasks pointing to the
init_task_group.  When a task calls setsid(), a new task group
is created, the process is moved into the new task group, and a
reference to the preveious task group is dropped.  Child
processes inherit this task group thereafter, and increase it's
refcount.  When the last thread of a process exits, the
process's reference is dropped, such that when the last process
referencing an autogroup exits, the autogroup is destroyed.

At runqueue selection time, IFF a task has no cgroup assignment,
its current autogroup is used.

Autogroup bandwidth is controllable via setting it's nice level
through the proc filesystem:

  cat /proc/<pid>/autogroup

Displays the task's group and the group's nice level.

  echo <nice level> > /proc/<pid>/autogroup

Sets the task group's shares to the weight of nice <level> task.
Setting nice level is rate limited for !admin users due to the
abuse risk of task group locking.

The feature is enabled from boot by default if
CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via
the boot option noautogroup, and can also be turned on/off on
the fly via:

  echo [01] > /proc/sys/kernel/sched_autogroup_enabled

... which will automatically move tasks to/from the root task group.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
[ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-30 16:03:35 +01:00
Paul E. McKenney
950eaaca68 pid: make setpgid() system call use RCU read-side critical section
[   23.584719]
[   23.584720] ===================================================
[   23.585059] [ INFO: suspicious rcu_dereference_check() usage. ]
[   23.585176] ---------------------------------------------------
[   23.585176] kernel/pid.c:419 invoked rcu_dereference_check() without protection!
[   23.585176]
[   23.585176] other info that might help us debug this:
[   23.585176]
[   23.585176]
[   23.585176] rcu_scheduler_active = 1, debug_locks = 1
[   23.585176] 1 lock held by rc.sysinit/728:
[   23.585176]  #0:  (tasklist_lock){.+.+..}, at: [<ffffffff8104771f>] sys_setpgid+0x5f/0x193
[   23.585176]
[   23.585176] stack backtrace:
[   23.585176] Pid: 728, comm: rc.sysinit Not tainted 2.6.36-rc2 #2
[   23.585176] Call Trace:
[   23.585176]  [<ffffffff8105b436>] lockdep_rcu_dereference+0x99/0xa2
[   23.585176]  [<ffffffff8104c324>] find_task_by_pid_ns+0x50/0x6a
[   23.585176]  [<ffffffff8104c35b>] find_task_by_vpid+0x1d/0x1f
[   23.585176]  [<ffffffff81047727>] sys_setpgid+0x67/0x193
[   23.585176]  [<ffffffff810029eb>] system_call_fastpath+0x16/0x1b
[   24.959669] type=1400 audit(1282938522.956:4): avc:  denied  { module_request } for  pid=766 comm="hwclock" kmod="char-major-10-135" scontext=system_u:system_r:hwclock_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclas

It turns out that the setpgid() system call fails to enter an RCU
read-side critical section before doing a PID-to-task_struct translation.
This commit therefore does rcu_read_lock() before the translation, and
also does rcu_read_unlock() after the last use of the returned pointer.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
2010-08-31 17:00:18 -07:00
Jiri Slaby
c022a0acad rlimits: implement prlimit64 syscall
This patch adds the code to support the sys_prlimit64 syscall which
modifies-and-returns the rlim values of a selected process atomically.
The first parameter, pid, being 0 means current process.

Unlike the current implementation, it is a generic interface,
architecture indepentent so that we needn't handle compat stuff
anymore. In the future, after glibc start to use this we can deprecate
sys_setrlimit and sys_getrlimit in favor to clean up the code finally.

It also adds a possibility of changing limits of other processes. We
check the user's permissions to do that and if it succeeds, the new
limits are propagated online. This is good for large scale
applications such as SAP or databases where administrators need to
change limits time by time (e.g. on crashes increase core size). And
it is unacceptable to restart the service.

For safety, all rlim users now either use accessors or doesn't need
them due to
- locking
- the fact a process was just forked and nobody else knows about it
  yet (and nobody can't thus read/write limits)
hence it is safe to modify limits now.

The limitation is that we currently stay at ulong internal
representation. So the rlim64_is_infinity check is used where value is
compared against ULONG_MAX on 32-bit which is the maximum value there.

And since internally the limits are held in struct rlimit, converters
which are used before and after do_prlimit call in sys_prlimit64 are
introduced.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2010-07-16 09:48:48 +02:00
Jiri Slaby
b95183453a rlimits: switch more rlimit syscalls to do_prlimit
After we added more generic do_prlimit, switch sys_getrlimit to that.
Also switch compat handling, so we can get rid of ugly __user casts
and avoid setting process' address limit to kernel data and back.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2010-07-16 09:48:48 +02:00
Jiri Slaby
5b41535aac rlimits: redo do_setrlimit to more generic do_prlimit
It now allows also reading of limits. I.e. all read and writes will
later use this function.

It takes two parameters, new and old limits which can be both NULL.
If new is non-NULL, the value in it is set to rlimits.
If old is non-NULL, current rlimits are stored there.
If both are non-NULL, old are stored prior to setting the new ones,
atomically.
(Similar to sigaction.)

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2010-07-16 09:48:48 +02:00
Jiri Slaby
86f162f4c7 rlimits: do security check under task_lock
Do security_task_setrlimit under task_lock. Other tasks may change
limits under our hands while we are checking limits inside the
function. From now on, they can't.

Note that all the security work is done under a spinlock here now.
Security hooks count with that, they are called from interrupt context
(like security_task_kill) and with spinlocks already held (e.g.
capable->security_capable).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: James Morris <jmorris@namei.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
2010-07-16 09:48:47 +02:00
Jiri Slaby
1c1e618ddd rlimits: allow setrlimit to non-current tasks
Add locking to allow setrlimit accept task parameter other than
current.

Namely, lock tasklist_lock for read and check whether the task
structure has sighand non-null. Do all the signal processing under
that lock still held.

There are some points:
1) security_task_setrlimit is now called with that lock held. This is
   not new, many security_* functions are called with this lock held
   already so it doesn't harm (all this security_* stuff does almost
   the same).
2) task->sighand->siglock (in update_rlimit_cpu) is nested in
   tasklist_lock. This dependence is already existing.
3) tsk->alloc_lock is nested in tasklist_lock. This is OK too, already
   existing dependence.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
2010-07-16 09:48:47 +02:00
Jiri Slaby
7855c35da7 rlimits: split sys_setrlimit
Create do_setrlimit from sys_setrlimit and declare do_setrlimit
in the resource header. This is the first phase to have generic
do_prlimit which allows to be called from read, write and compat
rlimits code.

The new do_setrlimit also accepts a task pointer to change the limits
of. Currently, it cannot be other than current, but this will change
with locking later.

Also pass tsk->group_leader to security_task_setrlimit to check
whether current is allowed to change rlimits of the process and not
its arbitrary thread because it makes more sense given that rlimit are
per process and not per-thread.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2010-07-16 09:48:46 +02:00
Oleg Nesterov
2fb9d2689a rlimits: make sure ->rlim_max never grows in sys_setrlimit
Mostly preparation for Jiri's changes, but probably makes sense anyway.

sys_setrlimit() checks new_rlim.rlim_max <= old_rlim->rlim_max, but when
it takes task_lock() old_rlim->rlim_max can be already lowered. Move this
check under task_lock().

Currently this is not important, we can only race with our sub-thread,
this means the application is stupid. But when we change the code to allow
the update of !current task's limits, it becomes important to make sure
->rlim_max can be lowered "reliably" even if we race with the application
doing sys_setrlimit().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2010-07-16 09:48:46 +02:00
Jiri Slaby
5ab46b345e rlimits: add task_struct to update_rlimit_cpu
Add task_struct as a parameter to update_rlimit_cpu to be able to set
rlimit_cpu of different task than current.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Acked-by: James Morris <jmorris@namei.org>
2010-07-16 09:48:45 +02:00
Jiri Slaby
8fd00b4d70 rlimits: security, add task_struct to setrlimit
Add task_struct to task_setrlimit of security_operations to be able to set
rlimit of task other than current.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
2010-07-16 09:48:45 +02:00
Neil Horman
a06a4dc3a0 kmod: add init function to usermodehelper
About 6 months ago, I made a set of changes to how the core-dump-to-a-pipe
feature in the kernel works.  We had reports of several races, including
some reports of apps bypassing our recursion check so that a process that
was forked as part of a core_pattern setup could infinitely crash and
refork until the system crashed.

We fixed those by improving our recursion checks.  The new check basically
refuses to fork a process if its core limit is zero, which works well.

Unfortunately, I've been getting grief from maintainer of user space
programs that are inserted as the forked process of core_pattern.  They
contend that in order for their programs (such as abrt and apport) to
work, all the running processes in a system must have their core limits
set to a non-zero value, to which I say 'yes'.  I did this by design, and
think thats the right way to do things.

But I've been asked to ease this burden on user space enough times that I
thought I would take a look at it.  The first suggestion was to make the
recursion check fail on a non-zero 'special' number, like one.  That way
the core collector process could set its core size ulimit to 1, and enable
the kernel's recursion detection.  This isn't a bad idea on the surface,
but I don't like it since its opt-in, in that if a program like abrt or
apport has a bug and fails to set such a core limit, we're left with a
recursively crashing system again.

So I've come up with this.  What I've done is modify the
call_usermodehelper api such that an extra parameter is added, a function
pointer which will be called by the user helper task, after it forks, but
before it exec's the required process.  This will give the caller the
opportunity to get a call back in the processes context, allowing it to do
whatever it needs to to the process in the kernel prior to exec-ing the
user space code.  In the case of do_coredump, this callback is ues to set
the core ulimit of the helper process to 1.  This elimnates the opt-in
problem that I had above, as it allows the ulimit for core sizes to be set
to the value of 1, which is what the recursion check looks for in
do_coredump.

This patch:

Create new function call_usermodehelper_fns() and allow it to assign both
an init and cleanup function, as we'll as arbitrary data.

The init function is called from the context of the forked process and
allows for customization of the helper process prior to calling exec.  Its
return code gates the continuation of the process, or causes its exit.
Also add an arbitrary data pointer to the subprocess_info struct allowing
for data to be passed from the caller to the new process, and the
subsequent cleanup process

Also, use this patch to cleanup the cleanup function.  It currently takes
an argp and envp pointer for freeing, which is ugly.  Lets instead just
make the subprocess_info structure public, and pass that to the cleanup
and init routines

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
James Morris
0ffbe2699c Merge branch 'master' into next 2010-05-06 10:56:07 +10:00
Andreas Schwab
46da276648 kernel/sys.c: fix compat uname machine
On ppc64 you get this error:

  $ setarch ppc -R true
  setarch: ppc: Unrecognized architecture

because uname still reports ppc64 as the machine.

So mask off the personality flags when checking for PER_LINUX32.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-24 11:31:24 -07:00
Eric Paris
06ad187e28 security: remove dead hook task_setgid
Unused hook.  Remove.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-12 12:19:17 +10:00
Eric Paris
43ed8c3b45 security: remove dead hook task_setuid
Unused hook.  Remove.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-12 12:19:16 +10:00
Tejun Heo
5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Christoph Hellwig
5cacdb4add Add generic sys_olduname()
Add generic implementations of the old and really old uname system calls.
Note that sh only implements sys_olduname but not sys_oldolduname, but I'm
not going to bother with another ifdef for that special case.

m32r implemented an old uname but never wired it up, so kill it, too.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:32 -08:00
Christoph Hellwig
e28cbf2293 improve sys_newuname() for compat architectures
On an architecture that supports 32-bit compat we need to override the
reported machine in uname with the 32-bit value.  Instead of doing this
separately in every architecture introduce a COMPAT_UTS_MACHINE define in
<asm/compat.h> and apply it directly in sys_newuname().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:32 -08:00
Jiri Slaby
78d7d407b6 kernel core: use helpers for rlimits
Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in commit 3e10e716ab ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:33 -08:00
Linus Torvalds
f66ffdedbf Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (25 commits)
  sched: Fix SCHED_MC regression caused by change in sched cpu_power
  sched: Don't use possibly stale sched_class
  kthread, sched: Remove reference to kthread_create_on_cpu
  sched: cpuacct: Use bigger percpu counter batch values for stats counters
  percpu_counter: Make __percpu_counter_add an inline function on UP
  sched: Remove member rt_se from struct rt_rq
  sched: Change usage of rt_rq->rt_se to rt_rq->tg->rt_se[cpu]
  sched: Remove unused update_shares_locked()
  sched: Use for_each_bit
  sched: Queue a deboosted task to the head of the RT prio queue
  sched: Implement head queueing for sched_rt
  sched: Extend enqueue_task to allow head queueing
  sched: Remove USER_SCHED
  sched: Fix the place where group powers are updated
  sched: Assume *balance is valid
  sched: Remove load_balance_newidle()
  sched: Unify load_balance{,_newidle}()
  sched: Add a lock break for PREEMPT=y
  sched: Remove from fwd decls
  sched: Remove rq_iterator from move_one_task
  ...

Fix up trivial conflicts in kernel/sched.c
2010-02-28 10:31:01 -08:00
Tetsuo Handa
701188374b kernel/sys.c: fix missing rcu protection for sys_getpriority()
find_task_by_vpid() is not safe without rcu_read_lock().  2.6.33-rc7 got
RCU protection for sys_setpriority() but missed it for sys_getpriority().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-22 19:50:34 -08:00
Dhaval Giani
7c9414385e sched: Remove USER_SCHED
Remove the USER_SCHED feature. It has been scheduled to be removed in
2.6.34 as per http://marc.info/?l=linux-kernel&m=125728479022976&w=2

Signed-off-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1263990378.24844.3.camel@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-21 13:40:18 +01:00
Linus Torvalds
10e5453ffa Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sys: Fix missing rcu protection for __task_cred() access
  signals: Fix more rcu assumptions
  signal: Fix racy access to __task_cred in kill_pid_info_as_uid()
2009-12-19 09:47:34 -08:00
H Hartley Sweeten
dfc6a736d4 kernel/sys.c: fix "warning: do-while statement is not a compound statement" noise
do_each_thread/while_each_thread wrap a block of code that is in this format:

	for (...)
		do
			...
		while

If curly braces do not surround the inner loop the following warning is
generated by sparse:

	warning: do-while statement is not a compound statement

Fix the warning by adding the braces.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:26 -08:00
Thomas Gleixner
d4581a239a sys: Fix missing rcu protection for __task_cred() access
commit c69e8d9 (CRED: Use RCU to access another task's creds and to
release a task's own creds) added non rcu_read_lock() protected access
to task creds of the target task in set_prio_one().

The comment above the function says:
 * - the caller must hold the RCU read lock

The calling code in sys_setpriority does read_lock(&tasklist_lock) but
not rcu_read_lock(). This works only when CONFIG_TREE_PREEMPT_RCU=n.
With CONFIG_TREE_PREEMPT_RCU=y the rcu_callbacks can run in the tick
interrupt when they see no read side critical section.

There is another instance of __task_cred() in sys_setpriority() itself
which is equally unprotected.

Wrap the whole code section into a rcu read side critical section to
fix this quick and dirty.

Will be revisited in course of the read_lock(&tasklist_lock) -> rcu
crusade.

Oleg noted further:

This also fixes another bug here. find_task_by_vpid() is not safe
without rcu_read_lock(). I do not mean it is not safe to use the
result, just find_pid_ns() by itself is not safe.

Usually tasklist gives enough protection, but if copy_process() fails
it calls free_pid() lockless and does call_rcu(delayed_put_pid().
This means, without rcu lock find_pid_ns() can't scan the hash table
safely.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091210004703.029784964@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2009-12-10 23:04:11 +01:00
Linus Torvalds
3b8ecd2244 Merge branch 'bkl-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'bkl-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sys: Remove BKL from sys_reboot
  pm_qos: clean up racy global "name" variable
  pm_qos: remove BKL
2009-12-09 08:07:17 -08:00
Hidetoshi Seto
0cf55e1ec0 sched, cputime: Introduce thread_group_times()
This is a real fix for problem of utime/stime values decreasing
described in the thread:

   http://lkml.org/lkml/2009/11/3/522

Now cputime is accounted in the following way:

 - {u,s}time in task_struct are increased every time when the thread
   is interrupted by a tick (timer interrupt).

 - When a thread exits, its {u,s}time are added to signal->{u,s}time,
   after adjusted by task_times().

 - When all threads in a thread_group exits, accumulated {u,s}time
   (and also c{u,s}time) in signal struct are added to c{u,s}time
   in signal struct of the group's parent.

So {u,s}time in task struct are "raw" tick count, while
{u,s}time and c{u,s}time in signal struct are "adjusted" values.

And accounted values are used by:

 - task_times(), to get cputime of a thread:
   This function returns adjusted values that originates from raw
   {u,s}time and scaled by sum_exec_runtime that accounted by CFS.

 - thread_group_cputime(), to get cputime of a thread group:
   This function returns sum of all {u,s}time of living threads in
   the group, plus {u,s}time in the signal struct that is sum of
   adjusted cputimes of all exited threads belonged to the group.

The problem is the return value of thread_group_cputime(),
because it is mixed sum of "raw" value and "adjusted" value:

  group's {u,s}time = foreach(thread){{u,s}time} + exited({u,s}time)

This misbehavior can break {u,s}time monotonicity.
Assume that if there is a thread that have raw values greater
than adjusted values (e.g. interrupted by 1000Hz ticks 50 times
but only runs 45ms) and if it exits, cputime will decrease (e.g.
-5ms).

To fix this, we could do:

  group's {u,s}time = foreach(t){task_times(t)} + exited({u,s}time)

But task_times() contains hard divisions, so applying it for
every thread should be avoided.

This patch fixes the above problem in the following way:

 - Modify thread's exit (= __exit_signal()) not to use task_times().
   It means {u,s}time in signal struct accumulates raw values instead
   of adjusted values.  As the result it makes thread_group_cputime()
   to return pure sum of "raw" values.

 - Introduce a new function thread_group_times(*task, *utime, *stime)
   that converts "raw" values of thread_group_cputime() to "adjusted"
   values, in same calculation procedure as task_times().

 - Modify group's exit (= wait_task_zombie()) to use this introduced
   thread_group_times().  It make c{u,s}time in signal struct to
   have adjusted values like before this patch.

 - Replace some thread_group_cputime() by thread_group_times().
   This replacements are only applied where conveys the "adjusted"
   cputime to users, and where already uses task_times() near by it.
   (i.e. sys_times(), getrusage(), and /proc/<PID>/stat.)

This patch have a positive side effect:

 - Before this patch, if a group contains many short-life threads
   (e.g. runs 0.9ms and not interrupted by ticks), the group's
   cputime could be invisible since thread's cputime was accumulated
   after adjusted: imagine adjustment function as adj(ticks, runtime),
     {adj(0, 0.9) + adj(0, 0.9) + ....} = {0 + 0 + ....} = 0.
   After this patch it will not happen because the adjustment is
   applied after accumulated.

v2:
 - remove if()s, put new variables into signal_struct.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Spencer Candland <spencer@bluehost.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
LKML-Reference: <4B162517.8040909@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-02 17:32:40 +01:00
Hidetoshi Seto
d180c5bcce sched: Introduce task_times() to replace task_{u,s}time() pair
Functions task_{u,s}time() are called in pair in almost all
cases.  However task_stime() is implemented to call task_utime()
from its inside, so such paired calls run task_utime() twice.

It means we do heavy divisions (div_u64 + do_div) twice to get
utime and stime which can be obtained at same time by one set
of divisions.

This patch introduces a function task_times(*tsk, *utime,
*stime) to retrieve utime and stime at once in better, optimized
way.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Spencer Candland <spencer@bluehost.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
LKML-Reference: <4B0E16AE.906@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26 12:59:19 +01:00
Linus Torvalds
3242f9804b Merge branch 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  HWPOISON: fix invalid page count in printk output
  HWPOISON: Allow schedule_on_each_cpu() from keventd
  HWPOISON: fix/proc/meminfo alignment
  HWPOISON: fix oops on ksm pages
  HWPOISON: Fix page count leak in hwpoison late kill in do_swap_page
  HWPOISON: return early on non-LRU pages
  HWPOISON: Add brief hwpoison description to Documentation
  HWPOISON: Clean up PR_MCE_KILL interface
2009-10-29 08:20:00 -07:00
Christian Borntraeger
0d0df599f1 connector: fix regression introduced by sid connector
Since commit 02b51df1b0 (proc connector: add
event for process becoming session leader) we have the following warning:

Badness at kernel/softirq.c:143
[...]
Krnl PSW : 0404c00180000000 00000000001481d4 (local_bh_enable+0xb0/0xe0)
[...]
Call Trace:
([<000000013fe04100>] 0x13fe04100)
 [<000000000048a946>] sk_filter+0x9a/0xd0
 [<000000000049d938>] netlink_broadcast+0x2c0/0x53c
 [<00000000003ba9ae>] cn_netlink_send+0x272/0x2b0
 [<00000000003baef0>] proc_sid_connector+0xc4/0xd4
 [<0000000000142604>] __set_special_pids+0x58/0x90
 [<0000000000159938>] sys_setsid+0xb4/0xd8
 [<00000000001187fe>] sysc_noemu+0x10/0x16
 [<00000041616cb266>] 0x41616cb266

The warning is
--->    WARN_ON_ONCE(in_irq() || irqs_disabled());

The network code must not be called with disabled interrupts but
sys_setsid holds the tasklist_lock with spinlock_irq while calling the
connector.

After a discussion we agreed that we can move proc_sid_connector from
__set_special_pids to sys_setsid.

We also agreed that it is sufficient to change the check from
task_session(curr) != pid into err > 0, since if we don't change the
session, this means we were already the leader and return -EPERM.

One last thing:
There is also daemonize(), and some people might want to get a
notification in that case. Since daemonize() is only needed if a user
space does kernel_thread this does not look important (and there seems
to be no consensus if this connector should be called in daemonize). If
we really want this, we can add proc_sid_connector to daemonize() in an
additional patch (Scott?)

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Scott James Remnant <scott@ubuntu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:25 -07:00
Thomas Gleixner
6f15fa5008 sys: Remove BKL from sys_reboot
Serialization of sys_reboot can be done local. The BKL is not
protecting anything else.

LKML-Reference: <20091010153349.405590702@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-10-14 15:31:10 +02:00
Andi Kleen
1087e9b4ff HWPOISON: Clean up PR_MCE_KILL interface
While writing the manpage I noticed some shortcomings in the
current interface.

- Define symbolic names for all the different values
- Boundary check the kill mode values
- For symmetry add a get interface too. This allows library
code to get/set the current state.
- For consistency define a PR_MCE_KILL_DEFAULT value

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-10-04 03:23:17 +02:00
Linus Torvalds
db16826367 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
  HWPOISON: Enable error_remove_page on btrfs
  HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
  HWPOISON: Add madvise() based injector for hardware poisoned pages v4
  HWPOISON: Enable error_remove_page for NFS
  HWPOISON: Enable .remove_error_page for migration aware file systems
  HWPOISON: The high level memory error handler in the VM v7
  HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
  HWPOISON: shmem: call set_page_dirty() with locked page
  HWPOISON: Define a new error_remove_page address space op for async truncation
  HWPOISON: Add invalidate_inode_page
  HWPOISON: Refactor truncate to allow direct truncating of page v2
  HWPOISON: check and isolate corrupted free pages v2
  HWPOISON: Handle hardware poisoned pages in try_to_unmap
  HWPOISON: Use bitmask/action code for try_to_unmap behaviour
  HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
  HWPOISON: Add poison check to page fault handling
  HWPOISON: Add basic support for poisoned pages in fault handler v3
  HWPOISON: Add new SIGBUS error codes for hardware poison signals
  HWPOISON: Add support for poison swap entries v2
  HWPOISON: Export some rmap vma locking to outside world
  ...
2009-09-24 07:53:22 -07:00
Jiri Pirko
1f10206cf8 getrusage: fill ru_maxrss value
Make ->ru_maxrss value in struct rusage filled accordingly to rss hiwater
mark.  This struct is filled as a parameter to getrusage syscall.
->ru_maxrss value is set to KBs which is the way it is done in BSD
systems.  /usr/bin/time (gnu time) application converts ->ru_maxrss to KBs
which seems to be incorrect behavior.  Maintainer of this util was
notified by me with the patch which corrects it and cc'ed.

To make this happen we extend struct signal_struct by two fields.  The
first one is ->maxrss which we use to store rss hiwater of the task.  The
second one is ->cmaxrss which we use to store highest rss hiwater of all
task childs.  These values are used in k_getrusage() to actually fill
->ru_maxrss.  k_getrusage() uses current rss hiwater value directly if mm
struct exists.

Note:
exec() clear mm->hiwater_rss, but doesn't clear sig->maxrss.
it is intetionally behavior. *BSD getrusage have exec() inheriting.

test programs
========================================================

getrusage.c
===========
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 #include <signal.h>
 #include <sys/mman.h>

 #include "common.h"

 #define err(str) perror(str), exit(1)

int main(int argc, char** argv)
{
	int status;

	printf("allocate 100MB\n");
	consume(100);

	printf("testcase1: fork inherit? \n");
	printf("  expect: initial.self ~= child.self\n");
	show_rusage("initial");
	if (__fork()) {
		wait(&status);
	} else {
		show_rusage("fork child");
		_exit(0);
	}
	printf("\n");

	printf("testcase2: fork inherit? (cont.) \n");
	printf("  expect: initial.children ~= 100MB, but child.children = 0\n");
	show_rusage("initial");
	if (__fork()) {
		wait(&status);
	} else {
		show_rusage("child");
		_exit(0);
	}
	printf("\n");

	printf("testcase3: fork + malloc \n");
	printf("  expect: child.self ~= initial.self + 50MB\n");
	show_rusage("initial");
	if (__fork()) {
		wait(&status);
	} else {
		printf("allocate +50MB\n");
		consume(50);
		show_rusage("fork child");
		_exit(0);
	}
	printf("\n");

	printf("testcase4: grandchild maxrss\n");
	printf("  expect: post_wait.children ~= 300MB\n");
	show_rusage("initial");
	if (__fork()) {
		wait(&status);
		show_rusage("post_wait");
	} else {
		system("./child -n 0 -g 300");
		_exit(0);
	}
	printf("\n");

	printf("testcase5: zombie\n");
	printf("  expect: pre_wait ~= initial, IOW the zombie process is not accounted.\n");
	printf("          post_wait ~= 400MB, IOW wait() collect child's max_rss. \n");
	show_rusage("initial");
	if (__fork()) {
		sleep(1); /* children become zombie */
		show_rusage("pre_wait");
		wait(&status);
		show_rusage("post_wait");
	} else {
		system("./child -n 400");
		_exit(0);
	}
	printf("\n");

	printf("testcase6: SIG_IGN\n");
	printf("  expect: initial ~= after_zombie (child's 500MB alloc should be ignored).\n");
	show_rusage("initial");
	signal(SIGCHLD, SIG_IGN);
	if (__fork()) {
		sleep(1); /* children become zombie */
		show_rusage("after_zombie");
	} else {
		system("./child -n 500");
		_exit(0);
	}
	printf("\n");
	signal(SIGCHLD, SIG_DFL);

	printf("testcase7: exec (without fork) \n");
	printf("  expect: initial ~= exec \n");
	show_rusage("initial");
	execl("./child", "child", "-v", NULL);

	return 0;
}

child.c
=======
 #include <sys/types.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/resource.h>

 #include "common.h"

int main(int argc, char** argv)
{
	int status;
	int c;
	long consume_size = 0;
	long grandchild_consume_size = 0;
	int show = 0;

	while ((c = getopt(argc, argv, "n:g:v")) != -1) {
		switch (c) {
		case 'n':
			consume_size = atol(optarg);
			break;
		case 'v':
			show = 1;
			break;
		case 'g':

			grandchild_consume_size = atol(optarg);
			break;
		default:
			break;
		}
	}

	if (show)
		show_rusage("exec");

	if (consume_size) {
		printf("child alloc %ldMB\n", consume_size);
		consume(consume_size);
	}

	if (grandchild_consume_size) {
		if (fork()) {
			wait(&status);
		} else {
			printf("grandchild alloc %ldMB\n", grandchild_consume_size);
			consume(grandchild_consume_size);

			exit(0);
		}
	}

	return 0;
}

common.c
========
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 #include <signal.h>
 #include <sys/mman.h>

 #include "common.h"
 #define err(str) perror(str), exit(1)

void show_rusage(char *prefix)
{
    	int err, err2;
    	struct rusage rusage_self;
    	struct rusage rusage_children;

    	printf("%s: ", prefix);
    	err = getrusage(RUSAGE_SELF, &rusage_self);
    	if (!err)
    		printf("self %ld ", rusage_self.ru_maxrss);
    	err2 = getrusage(RUSAGE_CHILDREN, &rusage_children);
    	if (!err2)
    		printf("children %ld ", rusage_children.ru_maxrss);

    	printf("\n");
}

/* Some buggy OS need this worthless CPU waste. */
void make_pagefault(void)
{
	void *addr;
	int size = getpagesize();
	int i;

	for (i=0; i<1000; i++) {
		addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
		if (addr == MAP_FAILED)
			err("make_pagefault");
		memset(addr, 0, size);
		munmap(addr, size);
	}
}

void consume(int mega)
{
    	size_t sz = mega * 1024 * 1024;
    	void *ptr;

    	ptr = malloc(sz);
    	memset(ptr, 0, sz);
	make_pagefault();
}

pid_t __fork(void)
{
	pid_t pid;

	pid = fork();
	make_pagefault();

	return pid;
}

common.h
========
void show_rusage(char *prefix);
void make_pagefault(void);
void consume(int mega);
pid_t __fork(void);

FreeBSD result (expected result)
========================================================
allocate 100MB
testcase1: fork inherit?
  expect: initial.self ~= child.self
initial: self 103492 children 0
fork child: self 103540 children 0

testcase2: fork inherit? (cont.)
  expect: initial.children ~= 100MB, but child.children = 0
initial: self 103540 children 103540
child: self 103564 children 0

testcase3: fork + malloc
  expect: child.self ~= initial.self + 50MB
initial: self 103564 children 103564
allocate +50MB
fork child: self 154860 children 0

testcase4: grandchild maxrss
  expect: post_wait.children ~= 300MB
initial: self 103564 children 154860
grandchild alloc 300MB
post_wait: self 103564 children 308720

testcase5: zombie
  expect: pre_wait ~= initial, IOW the zombie process is not accounted.
          post_wait ~= 400MB, IOW wait() collect child's max_rss.
initial: self 103564 children 308720
child alloc 400MB
pre_wait: self 103564 children 308720
post_wait: self 103564 children 411312

testcase6: SIG_IGN
  expect: initial ~= after_zombie (child's 500MB alloc should be ignored).
initial: self 103564 children 411312
child alloc 500MB
after_zombie: self 103624 children 411312

testcase7: exec (without fork)
  expect: initial ~= exec
initial: self 103624 children 411312
exec: self 103624 children 411312

Linux result (actual test result)
========================================================
allocate 100MB
testcase1: fork inherit?
  expect: initial.self ~= child.self
initial: self 102848 children 0
fork child: self 102572 children 0

testcase2: fork inherit? (cont.)
  expect: initial.children ~= 100MB, but child.children = 0
initial: self 102876 children 102644
child: self 102572 children 0

testcase3: fork + malloc
  expect: child.self ~= initial.self + 50MB
initial: self 102876 children 102644
allocate +50MB
fork child: self 153804 children 0

testcase4: grandchild maxrss
  expect: post_wait.children ~= 300MB
initial: self 102876 children 153864
grandchild alloc 300MB
post_wait: self 102876 children 307536

testcase5: zombie
  expect: pre_wait ~= initial, IOW the zombie process is not accounted.
          post_wait ~= 400MB, IOW wait() collect child's max_rss.
initial: self 102876 children 307536
child alloc 400MB
pre_wait: self 102876 children 307536
post_wait: self 102876 children 410076

testcase6: SIG_IGN
  expect: initial ~= after_zombie (child's 500MB alloc should be ignored).
initial: self 102876 children 410076
child alloc 500MB
after_zombie: self 102880 children 410076

testcase7: exec (without fork)
  expect: initial ~= exec
initial: self 102880 children 410076
exec: self 102880 children 410076

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:30 -07:00
Ingo Molnar
cdd6c482c9 perf: Do the big rename: Performance Counters -> Performance Events
Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\<event\>/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )

Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:28:04 +02:00
Andi Kleen
4db96cf077 HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
This allows processes to override their early/late kill
behaviour on hardware memory errors.

Typically applications which are memory error aware is
better of with early kill (see the error as soon
as possible), all others with late kill (only
see the error when the error is really impacting execution)

There's a global sysctl, but this way an application
can set its specific policy.

We're using two bits, one to signify that the process
stated its intention and that

I also made the prctl future proof by enforcing
the unused arguments are 0.

The state is inherited to children.

Note this makes us officially run out of process flags
on 32bit, but the next patch can easily add another field.

Manpage patch will be supplied separately.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-09-16 11:50:14 +02:00
Alexey Dobriyan
30639b6af8 groups: move code to kernel/groups.c
Move supplementary groups implementation to kernel/groups.c .
kernel/sys.c already accumulated quite a few random stuff.

Do strictly copy/paste + add required headers to compile.  Compile-tested
on many configs and archs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:48 -07:00
Ingo Molnar
e7fd5d4b3d Merge branch 'linus' into perfcounters/core
Merge reason: This brach was on -rc1, refresh it to almost-rc4 to pick up
              the latest upstream fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-29 14:47:05 +02:00
Andi Kleen
3d26dcf767 kernel/sys.c: clean up sys_shutdown exit path
Impact: cleanup, fix

Clean up sys_shutdown() exit path.  Factor out common code.  Return
correct error code instead of always 0 on failure.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-13 15:04:32 -07:00
Ingo Molnar
f541ae326f Merge branch 'linus' into perfcounters/core-v2
Merge reason: we have gathered quite a few conflicts, need to merge upstream

Conflicts:
	arch/powerpc/kernel/Makefile
	arch/x86/ia32/ia32entry.S
	arch/x86/include/asm/hardirq.h
	arch/x86/include/asm/unistd_32.h
	arch/x86/include/asm/unistd_64.h
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/irq.c
	arch/x86/kernel/syscall_table_32.S
	arch/x86/mm/iomap_32.c
	include/linux/sched.h
	kernel/Makefile

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-06 09:02:57 +02:00
Linus Torvalds
8fe74cf053 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  Remove two unneeded exports and make two symbols static in fs/mpage.c
  Cleanup after commit 585d3bc06f
  Trim includes of fdtable.h
  Don't crap into descriptor table in binfmt_som
  Trim includes in binfmt_elf
  Don't mess with descriptor table in load_elf_binary()
  Get rid of indirect include of fs_struct.h
  New helper - current_umask()
  check_unsafe_exec() doesn't care about signal handlers sharing
  New locking/refcounting for fs_struct
  Take fs_struct handling to new file (fs/fs_struct.c)
  Get rid of bumping fs_struct refcount in pivot_root(2)
  Kill unsharing fs_struct in __set_personality()
2009-04-02 21:09:10 -07:00
Oleg Nesterov
1b0f7ffd0e pids: kill signal_struct-> __pgrp/__session and friends
We are wasting 2 words in signal_struct without any reason to implement
task_pgrp_nr() and task_session_nr().

task_session_nr() has no callers since
2e2ba22ea4, we can remove it.

task_pgrp_nr() is still (I believe wrongly) used in fs/autofsX and
fs/coda.

This patch reimplements task_pgrp_nr() via task_pgrp_nr_ns(), and kills
__pgrp/__session and the related helpers.

The change in drivers/char/tty_io.c is cosmetic, but hopefully makes sense
anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Alan Cox <number6@the-village.bc.nu>		[tty parts]
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:02 -07:00
Al Viro
5ad4e53bd5 Get rid of indirect include of fs_struct.h
Don't pull it in sched.h; very few files actually need it and those
can include directly.  sched.h itself only needs forward declaration
of struct fs_struct;

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31 23:00:27 -04:00
Ingo Molnar
8163d88c79 Merge commit 'v2.6.29-rc7' into perfcounters/core
Conflicts:
	arch/x86/mm/iomap_32.c
2009-03-04 11:42:31 +01:00
Dhaval Giani
54e9912428 sched: don't allow setuid to succeed if the user does not have rt bandwidth
Impact: fix hung task with certain (non-default) rt-limit settings

Corey Hickey reported that on using setuid to change the uid of a
rt process, the process would be unkillable and not be running.
This is because there was no rt runtime for that user group. Add
in a check to see if a user can attach an rt task to its task group.
On failure, return EINVAL, which is also returned in
CONFIG_CGROUP_SCHED.

Reported-by: Corey Hickey <bugfood-ml@fatooh.org>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-27 11:11:53 +01:00
Ingo Molnar
95fd4845ed Merge commit 'v2.6.29-rc4' into perfcounters/core
Conflicts:
	arch/x86/kernel/setup_percpu.c
	arch/x86/mm/fault.c
	drivers/acpi/processor_idle.c
	kernel/irq/handle.c
2009-02-11 09:22:04 +01:00
Andrew Morton
60fd760fb9 revert "rlimit: permit setting RLIMIT_NOFILE to RLIM_INFINITY"
Revert commit 0c2d64fb6c because it causes
(arguably poorly designed) existing userspace to spend interminable
periods closing billions of not-open file descriptors.

We could bring this back, with some sort of opt-in tunable in /proc, which
defaults to "off".

Peter's alanysis follows:

: I spent several hours trying to get to the bottom of a serious
: performance issue that appeared on one of our servers after upgrading to
: 2.6.28.  In the end it's what could be considered a userspace bug that
: was triggered by a change in 2.6.28.  Since this might also affect other
: people I figured I'd at least document what I found here, and maybe we
: can even do something about it:
:
:
: So, I upgraded some of debian.org's machines to 2.6.28.1 and immediately
: the team maintaining our ftp archive complained that one of their
: scripts that previously ran in a few minutes still hadn't even come
: close to being done after an hour or so.  Downgrading to 2.6.27 fixed
: that.
:
: Turns out that script is forking a lot and something in it or python or
: whereever closes all the file descriptors it doesn't want to pass on.
: That is, it starts at zero and goes up to ulimit -n/RLIMIT_NOFILE and
: closes them all with a few exceptions.
:
: Turns out that takes a long time when your limit -n is now 2^20 (1048576).
:
: With 2.6.27.* the ulimit -n was the standard 1024, but with 2.6.28 it is
: now a thousand times that.
:
: 2.6.28 included a patch titled "rlimit: permit setting RLIMIT_NOFILE to
: RLIM_INFINITY" (0c2d64fb6c)[1] that
: allows, as the title implies, to set the limit for number of files to
: infinity.
:
: Closer investigation showed that the broken default ulimit did not apply
: to "system" processes (like stuff started from init).  In the end I
: could establish that all processes that passed through pam_limit at one
: point had the bad resource limit.
:
: Apparently the pam library in Debian etch (4.0) initializes the limits
: to some default values when it doesn't have any settings in limit.conf
: to override them.  Turns out that for nofiles this is RLIM_INFINITY.
: Commenting out "case RLIMIT_NOFILE" in pam_limit.c:267 of our pam
: package version 0.79-5 fixes that - tho I'm not sure what side effects
: that has.
:
: Debian lenny (the upcoming 5.0 version) doesn't have this issue as it
: uses a different pam (version).

Reported-by: Peter Palfrader <weasel@debian.org>
Cc: Adam Tkac <vonsch@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-05 12:56:47 -08:00
Ingo Molnar
77835492ed Merge commit 'v2.6.29-rc2' into perfcounters/core
Conflicts:
	include/linux/syscalls.h
2009-01-21 16:37:27 +01:00
Heiko Carstens
836f92adf1 [CVE-2009-0029] System call wrappers part 31
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:31 +01:00
Heiko Carstens
c4ea37c26a [CVE-2009-0029] System call wrappers part 26
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:29 +01:00
Heiko Carstens
e48fbb699f [CVE-2009-0029] System call wrappers part 24
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:28 +01:00
Heiko Carstens
5a8a82b1d3 [CVE-2009-0029] System call wrappers part 23
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:28 +01:00
Heiko Carstens
754fe8d297 [CVE-2009-0029] System call wrappers part 07
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:20 +01:00
Heiko Carstens
b290ebe2c4 [CVE-2009-0029] System call wrappers part 04
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:19 +01:00
Heiko Carstens
ae1251ab78 [CVE-2009-0029] System call wrappers part 03
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:19 +01:00
Heiko Carstens
dbf040d9d1 [CVE-2009-0029] System call wrappers part 02
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:19 +01:00
Heiko Carstens
58fd3aa288 [CVE-2009-0029] System call wrappers part 01
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:18 +01:00
Ingo Molnar
506c10f26c Merge commit 'v2.6.29-rc1' into perfcounters/core
Conflicts:
	include/linux/kernel_stat.h
2009-01-11 02:42:53 +01:00
Linus Torvalds
cfa97f993c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: fix section mismatch
  sched: fix double kfree in failure path
  sched: clean up arch_reinit_sched_domains()
  sched: mark sched_create_sysfs_power_savings_entries() as __init
  getrusage: RUSAGE_THREAD should return ru_utime and ru_stime
  sched: fix sched_slice()
  sched_clock: prevent scd->clock from moving backwards, take #2
  sched: sched.c declare variables before they get used
2009-01-06 17:10:33 -08:00
Paul Mackerras
e3d5a27d58 Allow times and time system calls to return small negative values
At the moment, the times() system call will appear to fail for a period
shortly after boot, while the value it want to return is between -4095 and
-1.  The same thing will also happen for the time() system call on 32-bit
platforms some time in 2106 or so.

On some platforms, such as x86, this is unavoidable because of the system
call ABI, but other platforms such as powerpc have a separate error
indication from the return value, so system calls can in fact return small
negative values without indicating an error.  On those platforms,
force_successful_syscall_return() provides a way to indicate that the
system call return value should not be treated as an error even if it is
in the range which would normally be taken as a negative error number.

This adds a force_successful_syscall_return() call to the time() and
times() system calls plus their 32-bit compat versions, so that they don't
erroneously indicate an error on those platforms whose system call ABI has
a separate error indication.  This will not affect anything on other
platforms.

Joakim Tjernlund added the fix for time() and the compat versions of
time() and times(), after I did the fix for times().

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:13 -08:00
KOSAKI Motohiro
8916edef58 getrusage: RUSAGE_THREAD should return ru_utime and ru_stime
Impact: task stats regression fix

Original getrusage(RUSAGE_THREAD) implementation can return ru_utime and
ru_stime. But commit "f06febc: timers: fix itimer/many thread hang" broke it.

this patch restores it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-04 14:04:00 +01:00
Linus Torvalds
5f34fe1cfc Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  stacktrace: provide save_stack_trace_tsk() weak alias
  rcu: provide RCU options on non-preempt architectures too
  printk: fix discarding message when recursion_bug
  futex: clean up futex_(un)lock_pi fault handling
  "Tree RCU": scalable classic RCU implementation
  futex: rename field in futex_q to clarify single waiter semantics
  x86/swiotlb: add default swiotlb_arch_range_needs_mapping
  x86/swiotlb: add default phys<->bus conversion
  x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
  x86: add swiotlb allocation functions
  swiotlb: consolidate swiotlb info message printing
  swiotlb: support bouncing of HighMem pages
  swiotlb: factor out copy to/from device
  swiotlb: add arch hook to force mapping
  swiotlb: allow architectures to override phys<->bus<->phys conversions
  swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
  rcu: fix rcutorture behavior during reboot
  resources: skip sanity check of busy resources
  swiotlb: move some definitions to header
  swiotlb: allow architectures to override swiotlb pool allocation
  ...

Fix up trivial conflicts in
  arch/x86/kernel/Makefile
  arch/x86/mm/init_32.c
  include/linux/hardirq.h
as per Ingo's suggestions.
2008-12-30 16:10:19 -08:00
Ingo Molnar
e1df957670 Merge branch 'linus' into perfcounters/core
Conflicts:
	fs/exec.c
	include/linux/init_task.h

Simple context conflicts.
2008-12-29 09:45:15 +01:00
Ingo Molnar
1d1c7ddbfa perf counters: add prctl interface to disable/enable counters
Add a way for self-monitoring tasks to disable/enable counters summarily,
via a prctl:

	PR_TASK_PERF_COUNTERS_DISABLE		31
	PR_TASK_PERF_COUNTERS_ENABLE		32

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-11 15:45:55 +01:00
Serge Hallyn
18b6e0414e User namespaces: set of cleanups (v2)
The user_ns is moved from nsproxy to user_struct, so that a struct
cred by itself is sufficient to determine access (which it otherwise
would not be).  Corresponding ecryptfs fixes (by David Howells) are
here as well.

Fix refcounting.  The following rules now apply:
        1. The task pins the user struct.
        2. The user struct pins its user namespace.
        3. The user namespace pins the struct user which created it.

User namespaces are cloned during copy_creds().  Unsharing a new user_ns
is no longer possible.  (We could re-add that, but it'll cause code
duplication and doesn't seem useful if PAM doesn't need to clone user
namespaces).

When a user namespace is created, its first user (uid 0) gets empty
keyrings and a clean group_info.

This incorporates a previous patch by David Howells.  Here
is his original patch description:

>I suggest adding the attached incremental patch.  It makes the following
>changes:
>
> (1) Provides a current_user_ns() macro to wrap accesses to current's user
>     namespace.
>
> (2) Fixes eCryptFS.
>
> (3) Renames create_new_userns() to create_user_ns() to be more consistent
>     with the other associated functions and because the 'new' in the name is
>     superfluous.
>
> (4) Moves the argument and permission checks made for CLONE_NEWUSER to the
>     beginning of do_fork() so that they're done prior to making any attempts
>     at allocation.
>
> (5) Calls create_user_ns() after prepare_creds(), and gives it the new creds
>     to fill in rather than have it return the new root user.  I don't imagine
>     the new root user being used for anything other than filling in a cred
>     struct.
>
>     This also permits me to get rid of a get_uid() and a free_uid(), as the
>     reference the creds were holding on the old user_struct can just be
>     transferred to the new namespace's creator pointer.
>
> (6) Makes create_user_ns() reset the UIDs and GIDs of the creds under
>     preparation rather than doing it in copy_creds().
>
>David

>Signed-off-by: David Howells <dhowells@redhat.com>

Changelog:
	Oct 20: integrate dhowells comments
		1. leave thread_keyring alone
		2. use current_user_ns() in set_user()

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
2008-11-24 18:57:41 -05:00
Oleg Nesterov
2b5fe6de58 thread_group_cputime: move a couple of callsites outside of ->siglock
Impact: relax the locking of cpu-time accounting calls

->siglock buys nothing for thread_group_cputime() in do_sys_times() and
wait_task_zombie() (which btw takes the unrelated parent's ->siglock).

Actually I think do_sys_times() doesn't need ->siglock at all.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-17 16:55:55 +01:00
David Howells
d84f4f992c CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management.  This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.

A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().

With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:

	struct cred *new = prepare_creds();
	int ret = blah(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}
	return commit_creds(new);

There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.

To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const.  The purpose of this is compile-time
discouragement of altering credentials through those pointers.  Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:

  (1) Its reference count may incremented and decremented.

  (2) The keyrings to which it points may be modified, but not replaced.

The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     This now prepares and commits credentials in various places in the
     security code rather than altering the current creds directly.

 (2) Temporary credential overrides.

     do_coredump() and sys_faccessat() now prepare their own credentials and
     temporarily override the ones currently on the acting thread, whilst
     preventing interference from other threads by holding cred_replace_mutex
     on the thread being dumped.

     This will be replaced in a future patch by something that hands down the
     credentials directly to the functions being called, rather than altering
     the task's objective credentials.

 (3) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_capset_check(), ->capset_check()
     (*) security_capset_set(), ->capset_set()

     	 Removed in favour of security_capset().

     (*) security_capset(), ->capset()

     	 New.  This is passed a pointer to the new creds, a pointer to the old
     	 creds and the proposed capability sets.  It should fill in the new
     	 creds or return an error.  All pointers, barring the pointer to the
     	 new creds, are now const.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()

     	 Changed; now returns a value, which will cause the process to be
     	 killed if it's an error.

     (*) security_task_alloc(), ->task_alloc_security()

     	 Removed in favour of security_prepare_creds().

     (*) security_cred_free(), ->cred_free()

     	 New.  Free security data attached to cred->security.

     (*) security_prepare_creds(), ->cred_prepare()

     	 New. Duplicate any security data attached to cred->security.

     (*) security_commit_creds(), ->cred_commit()

     	 New. Apply any security effects for the upcoming installation of new
     	 security by commit_creds().

     (*) security_task_post_setuid(), ->task_post_setuid()

     	 Removed in favour of security_task_fix_setuid().

     (*) security_task_fix_setuid(), ->task_fix_setuid()

     	 Fix up the proposed new credentials for setuid().  This is used by
     	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
     	 setuid() changes.  Changes are made to the new credentials, rather
     	 than the task itself as in security_task_post_setuid().

     (*) security_task_reparent_to_init(), ->task_reparent_to_init()

     	 Removed.  Instead the task being reparented to init is referred
     	 directly to init's credentials.

	 NOTE!  This results in the loss of some state: SELinux's osid no
	 longer records the sid of the thread that forked it.

     (*) security_key_alloc(), ->key_alloc()
     (*) security_key_permission(), ->key_permission()

     	 Changed.  These now take cred pointers rather than task pointers to
     	 refer to the security context.

 (4) sys_capset().

     This has been simplified and uses less locking.  The LSM functions it
     calls have been merged.

 (5) reparent_to_kthreadd().

     This gives the current thread the same credentials as init by simply using
     commit_thread() to point that way.

 (6) __sigqueue_alloc() and switch_uid()

     __sigqueue_alloc() can't stop the target task from changing its creds
     beneath it, so this function gets a reference to the currently applicable
     user_struct which it then passes into the sigqueue struct it returns if
     successful.

     switch_uid() is now called from commit_creds(), and possibly should be
     folded into that.  commit_creds() should take care of protecting
     __sigqueue_alloc().

 (7) [sg]et[ug]id() and co and [sg]et_current_groups.

     The set functions now all use prepare_creds(), commit_creds() and
     abort_creds() to build and check a new set of credentials before applying
     it.

     security_task_set[ug]id() is called inside the prepared section.  This
     guarantees that nothing else will affect the creds until we've finished.

     The calling of set_dumpable() has been moved into commit_creds().

     Much of the functionality of set_user() has been moved into
     commit_creds().

     The get functions all simply access the data directly.

 (8) security_task_prctl() and cap_task_prctl().

     security_task_prctl() has been modified to return -ENOSYS if it doesn't
     want to handle a function, or otherwise return the return value directly
     rather than through an argument.

     Additionally, cap_task_prctl() now prepares a new set of credentials, even
     if it doesn't end up using it.

 (9) Keyrings.

     A number of changes have been made to the keyrings code:

     (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
     	 all been dropped and built in to the credentials functions directly.
     	 They may want separating out again later.

     (b) key_alloc() and search_process_keyrings() now take a cred pointer
     	 rather than a task pointer to specify the security context.

     (c) copy_creds() gives a new thread within the same thread group a new
     	 thread keyring if its parent had one, otherwise it discards the thread
     	 keyring.

     (d) The authorisation key now points directly to the credentials to extend
     	 the search into rather pointing to the task that carries them.

     (e) Installing thread, process or session keyrings causes a new set of
     	 credentials to be created, even though it's not strictly necessary for
     	 process or session keyrings (they're shared).

(10) Usermode helper.

     The usermode helper code now carries a cred struct pointer in its
     subprocess_info struct instead of a new session keyring pointer.  This set
     of credentials is derived from init_cred and installed on the new process
     after it has been cloned.

     call_usermodehelper_setup() allocates the new credentials and
     call_usermodehelper_freeinfo() discards them if they haven't been used.  A
     special cred function (prepare_usermodeinfo_creds()) is provided
     specifically for call_usermodehelper_setup() to call.

     call_usermodehelper_setkeys() adjusts the credentials to sport the
     supplied keyring as the new session keyring.

(11) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) selinux_setprocattr() no longer does its check for whether the
     	 current ptracer can access processes with the new SID inside the lock
     	 that covers getting the ptracer's SID.  Whilst this lock ensures that
     	 the check is done with the ptracer pinned, the result is only valid
     	 until the lock is released, so there's no point doing it inside the
     	 lock.

(12) is_single_threaded().

     This function has been extracted from selinux_setprocattr() and put into
     a file of its own in the lib/ directory as join_session_keyring() now
     wants to use it too.

     The code in SELinux just checked to see whether a task shared mm_structs
     with other tasks (CLONE_VM), but that isn't good enough.  We really want
     to know if they're part of the same thread group (CLONE_THREAD).

(13) nfsd.

     The NFS server daemon now has to use the COW credentials to set the
     credentials it is going to use.  It really needs to pass the credentials
     down to the functions it calls, but it can't do that until other patches
     in this series have been applied.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:23 +11:00
David Howells
c69e8d9c01 CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:19 +11:00
David Howells
86a264abe5 CRED: Wrap current->cred and a few other accessors
Wrap current->cred and a few other accessors to hide their actual
implementation.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:18 +11:00
David Howells
b6dff3ec5e CRED: Separate task security context from task_struct
Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:16 +11:00
David Howells
76aac0e9a1 CRED: Wrap task credential accesses in the core kernel
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:12 +11:00
Thomas Gleixner
268a3dcfea Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2
Conflicts:

	kernel/time/tick-sched.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-22 09:48:06 +02:00
Thomas Gleixner
c465a76af6 Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus 2008-10-20 13:14:06 +02:00
Arjan van de Ven
651dab4264 Merge commit 'linus/master' into merge-linus
Conflicts:

	arch/x86/kvm/i8254.c
2008-10-17 09:20:26 -07:00
Andrew Morton
9679e4dd62 kernel/sys.c: improve code generation
utsname() is quite expensive to calculate.  Cache it in a local.

          text    data     bss     dec     hex filename
before:  11136     720      16   11872    2e60 kernel/sys.o
after:   11096     720      16   11832    2e38 kernel/sys.o

Acked-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:31 -07:00
Vegard Nossum
8798881507 utsname: completely overwrite prior information
On sethostname() and setdomainname(), previous information may be retained
if it was longer than than the new hostname/domainname.

This can be demonstrated trivially by calling sethostname() first with a
long name, then with a short name, and then calling uname() to retrieve
the full buffer that contains the hostname (and possibly parts of the old
hostname), one just has to look past the terminating zero.

I don't know if we should really care that much (hence the RFC); the only
scenarios I can possibly think of is administrator putting something
sensitive in the hostname (or domain name) by accident, and changing it
back will not undo the mistake entirely, though it's not like we can
recover gracefully from "rm -rf /" either...  The other scenario is
namespaces (CLONE_NEWUTS) where some information may be unintentionally
"inherited" from the previous namespace (a program wants to hide the
original name and does clone + sethostname, but some information is still
left).

I think the patch may be defended on grounds of the principle of least
surprise.  But I am not adamant :-)

(I guess the question now is whether userspace should be able to
write embedded NULs into the buffer or not...)

At least the observation has been made and the patch has been presented.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:31 -07:00
Adam Tkac
0c2d64fb6c rlimit: permit setting RLIMIT_NOFILE to RLIM_INFINITY
When a process wants to set the limit of open files to RLIM_INFINITY it
gets EPERM even if it has CAP_SYS_RESOURCE capability.

For example, BIND does:

...
#elif defined(NR_OPEN) && defined(__linux__)
        /*
         * Some Linux kernels don't accept RLIM_INFINIT; the maximum
         * possible value is the NR_OPEN defined in linux/fs.h.
         */
        if (resource == isc_resource_openfiles && rlim_value == RLIM_INFINITY) {
                rl.rlim_cur = rl.rlim_max = NR_OPEN;
                unixresult = setrlimit(unixresource, &rl);
                if (unixresult == 0)
                        return (ISC_R_SUCCESS);
        }
#elif ...

If we allow setting RLIMIT_NOFILE to RLIM_INFINITY we increase portability
- you don't have to check if OS is linux and then use different schema for
limits.

The spec says "Specifying RLIM_INFINITY as any resource limit value on a
successful call to setrlimit() shall inhibit enforcement of that resource
limit." and we're presently not doing that.

Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:31 -07:00
Alan Cox
9c9f4ded90 tty: Add a kref count
Introduce a kref to the tty structure and use it to protect the tty->signal
tty references. For now we don't introduce it for anything else.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Frank Mayhar
f06febc96b timers: fix itimer/many thread hang
Overview

This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling.  It was put together
with the help of Roland McGrath, the owner and original writer of this code.

The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads.  It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.

This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."

Code Changes

This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine.  (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.)  To do this, at each tick we now update fields in
signal_struct as well as task_struct.  The run_posix_cpu_timers() function
uses those fields to make its decisions.

We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:

struct task_cputime {
	cputime_t utime;
	cputime_t stime;
	unsigned long long sum_exec_runtime;
};

This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels.  For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:

struct thread_group_cputime {
	struct task_cputime totals;
};

struct thread_group_cputime {
	struct task_cputime *totals;
};

We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers).  The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends.  In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention).  For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu().  The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().

We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel.  The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields.  The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures.  The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated.  The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU.  Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.

Non-SMP operation is trivial and will not be mentioned further.

The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().

All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.

Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away.  All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline.  When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.

Performance

The fix appears not to add significant overhead to existing operations.  It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below).  Overall it's a wash except in those
two cases.

I've since done somewhat more involved testing on a dual-core Opteron system.

Case 1: With no itimer running, for a test with 100,000 threads, the fixed
	kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
	all of which was spent in the system.  There were twice as many
	voluntary context switches with the fix as without it.

Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
	an unmodified kernel can handle), the fixed kernel ran the test in
	eight percent of the time (5.8 seconds as opposed to 70 seconds) and
	had better tick accuracy (.012 seconds per tick as opposed to .023
	seconds per tick).

Case 3: A 4000-thread test with an initial timer tick of .01 second and an
	interval of 10,000 seconds (i.e. a timer that ticks only once) had
	very nearly the same performance in both cases:  6.3 seconds elapsed
	for the fixed kernel versus 5.5 seconds for the unfixed kernel.

With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds).  The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.

Since the fix affected the rlimit code, I also tested soft and hard CPU limits.

Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
	running), the modified kernel was very slightly favored in that while
	it killed the process in 19.997 seconds of CPU time (5.002 seconds of
	wall time), only .003 seconds of that was system time, the rest was
	user time.  The unmodified kernel killed the process in 20.001 seconds
	of CPU (5.014 seconds of wall time) of which .016 seconds was system
	time.  Really, though, the results were too close to call.  The results
	were essentially the same with no itimer running.

Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
	(where the hard limit would never be reached) and an itimer running,
	the modified kernel exhibited worse tick accuracy than the unmodified
	kernel: .050 seconds/tick versus .028 seconds/tick.  Otherwise,
	performance was almost indistinguishable.  With no itimer running this
	test exhibited virtually identical behavior and times in both cases.

In times past I did some limited performance testing.  those results are below.

On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s.  On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds.  Performance with eight, four and one
thread were comparable.  Interestingly, the timer ticks with the fix seemed
more accurate:  The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick.  Both cases were configured for an interval of
0.01 seconds.  Again, the other tests were comparable.  Each thread in this
test computed the primes up to 25,000,000.

I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix.  In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable).  System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s).  It received 147651 ticks for 0.015 seconds per tick, still quite
accurate.  There is obviously no comparable test without the fix.

Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-14 16:25:35 +02:00
Arjan van de Ven
6976675d94 hrtimer: create a "timer_slack" field in the task struct
We want to be able to control the default "rounding" that is used by
select() and poll() and friends. This is a per process property
(so that we can have a "nice" like program to start certain programs with
a looser or stricter rounding) that can be set/get via a prctl().

For this purpose, a field called "timer_slack_ns" is added to the task
struct. In addition, a field called "default_timer_slack"ns" is added
so that tasks easily can temporarily to a more/less accurate slack and then
back to the default.

The default value of the slack is set to 50 usec; this is significantly less
than 2.6.27's average select() and poll() timing error but still allows
the kernel to group timers somewhat to preserve power behavior. Applications
and admins can override this via the prctl()

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-09-05 21:35:30 -07:00
Ken Chen
2d70b68d42 fix setpriority(PRIO_PGRP) thread iterator breakage
When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP
process, only the task leader of the process is affected, all other
sibling LWP threads didn't receive the setting.  The problem was that the
iterator used in sys_setpriority() only iteartes over one task for each
process, ignoring all other sibling thread.

Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk
each thread of a process.  Convert 4 call sites in {set/get}priority and
ioprio_{set/get}.

Signed-off-by: Ken Chen <kenchen@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-20 15:40:32 -07:00
Huang Ying
ca195b7f6d kexec jump: remove duplication of kexec_restart_prepare()
Call kernel_restart_prepare() in kernel_kexec() instead of duplicating the
code.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-15 08:35:42 -07:00
Huang Ying
3ab8352137 kexec jump
This patch provides an enhancement to kexec/kdump.  It implements the
following features:

- Backup/restore memory used by the original kernel before/after
  kexec.

- Save/restore CPU state before/after kexec.

The features of this patch can be used as a general method to call program in
physical mode (paging turning off).  This can be used to call BIOS code under
Linux.

kexec-tools needs to be patched to support kexec jump. The patches and
the precompiled kexec can be download from the following URL:

       source: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-src_git_kh10.tar.bz2
       patches: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-patches_git_kh10.tar.bz2
       binary: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec_git_kh10

Usage example of calling some physical mode code and return:

1. Compile and install patched kernel with following options selected:

CONFIG_X86_32=y
CONFIG_KEXEC=y
CONFIG_PM=y
CONFIG_KEXEC_JUMP=y

2. Build patched kexec-tool or download the pre-built one.

3. Build some physical mode executable named such as "phy_mode"

4. Boot kernel compiled in step 1.

5. Load physical mode executable with /sbin/kexec. The shell command
   line can be as follow:

   /sbin/kexec --load-preserve-context --args-none phy_mode

6. Call physical mode executable with following shell command line:

   /sbin/kexec -e

Implementation point:

To support jumping without reserving memory.  One shadow backup page (source
page) is allocated for each page used by kexeced code image (destination
page).  When do kexec_load, the image of kexeced code is loaded into source
pages, and before executing, the destination pages and the source pages are
swapped, so the contents of destination pages are backupped.  Before jumping
to the kexeced code image and after jumping back to the original kernel, the
destination pages and the source pages are swapped too.

C ABI (calling convention) is used as communication protocol between
kernel and called code.

A flag named KEXEC_PRESERVE_CONTEXT for sys_kexec_load is added to
indicate that the loaded kernel image is used for jumping back.

Now, only the i386 architecture is supported.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:04 -07:00
Adrian Bunk
7394f0f6c0 unexport uts_sem
With the removal of the Solaris binary emulation the export of
uts_sem became unused.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:45 -07:00
KOSAKI Motohiro
ac331d158e call_usermodehelper(): increase reliability
Presently call_usermodehelper_setup() uses GFP_ATOMIC.  but it can return
NULL _very_ easily.

GFP_ATOMIC is needed only when we can't sleep.  and, GFP_KERNEL is robust
and better.

thus, I add gfp_mask argument to call_usermodehelper_setup().

So, its callers pass the gfp_t as below:

call_usermodehelper() and call_usermodehelper_keys():
	depend on 'wait' argument.
call_usermodehelper_pipe():
	always GFP_KERNEL because always run under process context.
orderly_poweroff():
	pass to GFP_ATOMIC because may run under interrupt context.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Paul Menage" <menage@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:28 -07:00
Shi Weihua
7b26655f62 sys_prctl(): fix return of uninitialized value
If none of the switch cases match, the PR_SET_PDEATHSIG and
PR_SET_DUMPABLE cases of the switch statement will never write to local
variable `error'.

Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Acked-by: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-24 09:56:13 -07:00
Oleg Nesterov
12a3de0a96 pids: sys_getpgid: fix unsafe *pid usage, s/tasklist/rcu/
1. sys_getpgid() needs rcu_read_lock() to derive the pgrp _nr, even if
   the task is current, otherwise we can race with another thread which
   does sys_setpgid().

2. Use rcu_read_lock() instead of tasklist_lock when pid != 0, make sure
   that we don't use the NULL pid if the task exits right after successful
   find_task_by_vpid().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:49 -07:00
Oleg Nesterov
1dd768c081 pids: sys_getsid: fix unsafe *pid usage, fix possible 0 instead of -ESRCH
1. sys_getsid() needs rcu_read_lock() to derive the session _nr, even if
   the task is current, otherwise we can race with another thread which
   does sys_setsid().

2. The task can exit between find_task_by_vpid() and task_session_vnr(),
   in that unlikely case sys_getsid() returns 0 instead of -ESRCH.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:49 -07:00
Oleg Nesterov
83beaf3c6c pids: sys_setpgid: use change_pid() helper
Use change_pid() instead of detach_pid() + attach_pid() in sys_setpgid().

This way task_pgrp() is not NULL in between.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc:  "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:49 -07:00
Oleg Nesterov
d6cf723a14 k_getrusage: don't take rcu_read_lock()
Just a trivial example, more to come.

k_getrusage() holds rcu_read_lock() because it was previously required by
lock_task_sighand().  Unneeded now.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:34 -07:00