Peter Zijlstra 631778f7c2 module: Fix locking in symbol_put_addr() ... commit 275d7d44d802ef271a42dc87ac091a495ba72fc5 upstream. Poma (on the way to another bug) reported an assertion triggering: [<ffffffff81150529>] module_assert_mutex_or_preempt+0x49/0x90 [<ffffffff81150822>] __module_address+0x32/0x150 [<ffffffff81150956>] __module_text_address+0x16/0x70 [<ffffffff81150f19>] symbol_put_addr+0x29/0x40 [<ffffffffa04b77ad>] dvb_frontend_detach+0x7d/0x90 [dvb_core] Laura Abbott <labbott@redhat.com> produced a patch which lead us to inspect symbol_put_addr(). This function has a comment claiming it doesn't need to disable preemption around the module lookup because it holds a reference to the module it wants to find, which therefore cannot go away. This is wrong (and a false optimization too, preempt_disable() is really rather cheap, and I doubt any of this is on uber critical paths, otherwise it would've retained a pointer to the actual module anyway and avoided the second lookup). While its true that the module cannot go away while we hold a reference on it, the data structure we do the lookup in very much _CAN_ change while we do the lookup. Therefore fix the comment and add the required preempt_disable(). Reported-by: poma <pomidorabelisima@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Fixes: a6e6abd575 ("module: remove module_text_address()") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2015-11-09 10:12:59 -08:00
..
cpu	sched, idle: Fix the idle polling state logic	2013-11-29 11:11:42 -08:00
debug	kdb: fix incorrect counts in KDB summary command output	2015-03-06 14:40:52 -08:00
events	perf: Fix fasync handling on inherited events	2015-09-13 09:07:59 -07:00
gcov
irq	genirq: Fix race in register_irq_proc()	2015-10-22 14:37:53 -07:00
power	PM / QoS: remove duplicate call to pm_qos_update_target	2015-03-18 13:22:28 +01:00
sched	printk: rename printk_sched to printk_deferred	2014-08-07 14:30:26 -07:00
time	ntp: Fixup adjtimex freq validation on 32-bit systems	2015-03-06 14:40:52 -08:00
trace	tracing: Have branch tracer use recursive field of task struct	2015-08-03 09:29:45 -07:00
.gitignore	kernel/hz.bc: ignore.	2013-04-22 07:09:06 -07:00
acct.c	fs: Fix hang with BSD accounting on frozen filesystem	2013-05-04 14:57:58 -04:00
async.c
audit.c	CAPABILITIES: remove undefined caps from all processes	2014-09-17 09:03:57 -07:00
audit.h	audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record	2013-12-04 10:57:03 -08:00
audit_tree.c	audit: keep inode pinned	2014-11-21 09:22:52 -08:00
audit_watch.c
auditfilter.c	auditfilter.c: fix kernel-doc warnings	2013-05-24 16:22:52 -07:00
auditsc.c	auditsc: audit_krule mask accesses need bounds checking	2014-06-16 13:42:53 -07:00
backtracetest.c
bounds.c
capability.c	CAPABILITIES: remove undefined caps from all processes	2014-09-17 09:03:57 -07:00
cgroup.c	move d_rcu from overlapping d_child to overlapping d_alias	2015-04-29 10:34:00 +02:00
cgroup_freezer.c
compat.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal	2013-05-01 07:21:43 -07:00
configs.c	proc: Supply PDE attribute setting accessor functions	2013-05-01 17:29:18 -04:00
context_tracking.c	Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-06-20 08:18:35 -10:00
cpu.c	sched: Fix hotplug vs. set_cpus_allowed_ptr()	2014-06-11 12:03:24 -07:00
cpu_pm.c
cpuset.c	cpuset,mempolicy: fix sleeping function called from invalid context	2014-07-17 15:58:00 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	introduce for_each_thread() to replace the buggy while_each_thread()	2014-10-05 14:54:15 -07:00
extable.c	extable: Flip the sorting message	2013-04-15 13:25:16 +02:00
fork.c	unshare: Unsharing a thread does not require unsharing a vm	2015-10-01 12:07:28 +02:00
freezer.c	freezer: Do not freeze tasks killed by OOM killer	2014-11-14 08:47:58 -08:00
futex.c	futex: Make lookup_pi_state more robust	2014-06-07 13:25:41 -07:00
futex_compat.c
groups.c	userns: Don't allow setgroups until a gid mapping has been setablished	2015-01-08 09:58:16 -08:00
hrtimer.c	hrtimer: Set expiry time before switch_hrtimer_base()	2014-06-07 13:25:31 -07:00
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c	kernel: kallsyms: memory override issue, need check destination buffer length	2013-04-15 15:17:26 +09:30
kcmp.c	kcmp: fix standard comparison bug	2014-10-05 14:54:13 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/mutex: Disable optimistic spinning on some architectures	2014-07-28 08:00:07 -07:00
Kconfig.preempt
kexec.c	PCI: Disable Bus Master only on kexec reboot	2013-12-20 07:45:08 -08:00
kmod.c	usermodehelper: check subprocess_info->path != NULL	2013-05-16 12:01:11 -07:00
kprobes.c	kprobes: Fix to free gone and unused optprobes	2013-05-28 10:37:59 +02:00
ksysfs.c
kthread.c	kthread: implement probe_kthread_data()	2013-04-30 17:04:02 -07:00
latencytop.c
lglock.c
lockdep.c	Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block	2013-05-08 11:51:05 -07:00
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
Makefile	We get rid of the general module prefix confusion with a binary config option,	2013-05-05 10:58:06 -07:00
modsign_certificate.S
modsign_pubkey.c
module-internal.h
module.c	module: Fix locking in symbol_put_addr()	2015-11-09 10:12:59 -08:00
module_signing.c
mutex-debug.c
mutex-debug.h
mutex.c	mutex: Back out architecture specific check for negative mutex count	2013-04-19 09:33:36 +02:00
mutex.h
notifier.c
nsproxy.c	proc: Split the namespace stuff out into linux/proc_ns.h	2013-05-01 17:29:39 -04:00
padata.c
panic.c	dump_stack: implement arch-specific hardware description in task dumps	2013-04-30 17:04:02 -07:00
params.c
pid.c	exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting	2015-01-08 09:58:17 -08:00
pid_namespace.c	pid_namespace: pidns_get() should check task_active_pid_ns() != NULL	2014-04-26 17:15:34 -07:00
posix-cpu-timers.c	posix_timers: Fix pre-condition to stop the tick on full dynticks	2013-04-22 19:59:25 +02:00
posix-timers.c	posix-timers: Fix stack info leak in timer_create()	2014-11-14 08:48:00 -08:00
printk.c	console: Fix console name size mismatch	2015-04-19 10:10:51 +02:00
profile.c	proc: Supply PDE attribute setting accessor functions	2013-05-01 17:29:18 -04:00
ptrace.c	__ptrace_may_access() should not deny sub-threads	2015-07-03 19:48:08 -07:00
range.c	range: Do not add new blank slot with add_range_with_merge	2013-06-18 11:32:10 -05:00
rcu.h
rcupdate.c
rcutiny.c
rcutiny_plugin.h
rcutorture.c
rcutree.c	rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration	2013-06-10 13:37:12 -07:00
rcutree.h	rcu: Don't call wakeup() with rcu_node structure ->lock held	2013-06-10 13:37:11 -07:00
rcutree_plugin.h	rcu: Don't allocate bootmem from rcu_init()	2013-05-15 10:41:12 -07:00
rcutree_trace.c	rcutrace: single_open() leaks	2013-05-05 00:16:35 -04:00
relay.c	Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block	2013-05-08 10:13:35 -07:00
res_counter.c
resource.c	mem hotunplug: fix kfree() of bootmem memory	2013-04-29 15:54:40 -07:00
rtmutex-debug.c
rtmutex-debug.h	rtmutex: Handle deadlock detection smarter	2014-07-17 15:58:04 -07:00
rtmutex-tester.c	locking/rtmutex/tester: Set correct permissions on sysfs files	2013-04-10 14:48:37 +02:00
rtmutex.c	rtmutex: Plug slow unlock race	2014-07-17 15:58:04 -07:00
rtmutex.h	rtmutex: Handle deadlock detection smarter	2014-07-17 15:58:04 -07:00
rtmutex_common.h
rwsem.c
seccomp.c
semaphore.c	semaphore: use `bool' type for semaphore_waiter's up	2013-04-30 17:04:08 -07:00
signal.c	signal: fix information leak in copy_siginfo_from_user32	2015-08-16 20:51:42 -07:00
smp.c	kernel/smp.c:on_each_cpu_cond(): fix warning in fallback path	2014-09-17 09:03:57 -07:00
smpboot.c	smpboot: Add missing get_online_cpus() in smpboot_register_percpu_thread()	2015-02-11 14:48:17 +08:00
smpboot.h
softirq.c	revert "softirq: Add support for triggering softirq work on softirqs"	2015-05-17 09:51:33 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys.c	reboot: rigrate shutdown/reboot to boot cpu	2013-06-12 16:29:44 -07:00
sys_ni.c	unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE	2013-05-09 13:46:38 -04:00
sysctl.c	perf: Enforce 1 as lower limit for perf_event_max_sample_rate	2014-06-11 12:03:27 -07:00
sysctl_binary.c	switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE	2013-05-09 14:53:20 -04:00
task_work.c
taskstats.c
test_kprobes.c	kernel/: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
time.c	time: settimeofday: Validate the values of tv from user	2015-01-29 17:40:56 -08:00
timeconst.bc
timer.c	timer: Prevent overflow in apply_slack	2014-06-07 13:25:30 -07:00
tracepoint.c	tracepoint: Do not waste memory on mods with no tracepoints	2014-05-30 21:52:11 -07:00
tsacct.c
uid16.c	groups: Consolidate the setgroups permission checks	2015-01-08 09:58:16 -08:00
up.c
user-return-notifier.c
user.c	userns: Add a knob to disable setgroups on a per user namespace basis	2015-01-08 09:58:16 -08:00
user_namespace.c	userns: Allow setting gid_maps without privilege when setgroups is disabled	2015-01-08 09:58:17 -08:00
utsname.c	proc: Split the namespace stuff out into linux/proc_ns.h	2013-05-01 17:29:39 -04:00
utsname_sysctl.c
wait.c
watchdog.c
workqueue.c	workqueue: make sure delayed work run in local cpu	2015-10-27 09:44:50 +09:00
workqueue_internal.h	workqueue: include workqueue info when printing debug dump of a worker task	2013-04-30 17:04:02 -07:00