Darren Hart beda2c7ea2 futex: Update futex_q lock_ptr on requeue proxy lock ... futex_requeue() can acquire the lock on behalf of a waiter early on or during the requeue loop if it is uncontended or in the event of a lock steal or owner died. On wakeup, the waiter (in futex_wait_requeue_pi()) cleans up the pi_state owner using the lock_ptr to protect against concurrent access to the pi_state. The pi_state is hung off futex_q's on the requeue target futex hash bucket so the lock_ptr needs to be updated accordingly. The problem manifested by triggering the WARN_ON in lookup_pi_state() about the pid != pi_state->owner->pid. With this patch, the pi_state is properly guarded against concurrent access via the requeue target hb lock. The astute reviewer may notice that there is a window of time between when futex_requeue() unlocks the hb locks and when futex_wait_requeue_pi() will acquire hb2->lock. During this time the pi_state and uval are not in sync with the underlying rtmutex owner (but the uval does indicate there are waiters, so no atomic changes will occur in userspace). However, this is not a problem. Should a contending thread enter lookup_pi_state() and acquire hb2->lock before the ownership is fixed up, it will find the pi_state hung off a waiter's (possibly the pending owner's) futex_q and block on the rtmutex. Once futex_wait_requeue_pi() fixes up the owner, it will also move the pi_state from the old owner's task->pi_state_list to its own. v3: Fix plist lock name for application to mainline (rather than -rt) Compile tested against tip/v2.6.31-rc5. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4A7F4EFF.6090903@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-08-10 11:07:03 +02:00
..
gcov	gcov: enable GCOV_PROFILE_ALL for x86_64	2009-06-18 13:03:58 -07:00
irq	genirq: Fix UP compile failure caused by irq_thread_check_affinity	2009-07-22 23:18:46 +02:00
power	headers: smp_lock.h redux	2009-07-12 12:22:34 -07:00
time	clocksource: Prevent NULL pointer dereference	2009-07-19 17:15:54 +02:00
trace	perf_counter: Fix/complete ftrace event records sampling	2009-08-09 12:53:48 +02:00
.gitignore
acct.c	bsdacct: fix access to invalid filp in acct_on()	2009-06-30 18:56:00 -07:00
async.c	async: Fix lack of boot-time console due to insufficient synchronization	2009-06-08 12:31:53 -07:00
audit.c	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit.h	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit_tree.c	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit_watch.c	Audit: clean up all op= output to include string quoting	2009-06-24 00:00:52 -04:00
auditfilter.c	Audit: clean up all op= output to include string quoting	2009-06-24 00:00:52 -04:00
auditsc.c	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
backtracetest.c
bounds.c
capability.c
cgroup.c	cgroup avoid permanent sleep at rmdir	2009-07-29 19:10:35 -07:00
cgroup_debug.c	debug cgroup: remove unneeded cgroup_lock	2009-04-02 19:04:54 -07:00
cgroup_freezer.c
compat.c	signals: implement sys_rt_tgsigqueueinfo	2009-04-30 19:24:24 +02:00
configs.c
cpu.c	mm/init: cpu_hotplug_init() must be initialized before SLAB	2009-06-22 21:18:12 -07:00
cpuset.c	cpuset,mm: update tasks' mems_allowed in time	2009-06-16 19:47:31 -07:00
cred-internals.h
cred.c	CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace	2009-05-11 08:15:36 +10:00
delayacct.c
dma-coherent.c
dma.c
exec_domain.c	Get rid of indirect include of fs_struct.h	2009-03-31 23:00:27 -04:00
exit.c	headers: mnt_namespace.h redux	2009-07-08 09:31:56 -07:00
extable.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
fork.c	execve: must clear current->clear_child_tid	2009-08-07 10:39:56 -07:00
freezer.c	sched: fix nr_uninterruptible accounting of frozen tasks really	2009-07-18 14:19:53 +02:00
futex.c	futex: Update futex_q lock_ptr on requeue proxy lock	2009-08-10 11:07:03 +02:00
futex_compat.c
groups.c	groups: move code to kernel/groups.c	2009-06-16 19:47:48 -07:00
hrtimer.c	hrtimer: Fix migration expiry check	2009-07-10 17:32:55 +02:00
hung_task.c
itimer.c
kallsyms.c	kernel/kallsyms.c: replace deprecated __initcall with device_initcall and fix whitespace	2009-06-09 22:37:52 +02:00
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c	kexec: fix omitting offset in extended crashkernel syntax	2009-07-29 19:10:34 -07:00
kfifo.c	kernel/kfifo.c: replace conditional test with is_power_of_2()	2009-06-16 19:47:47 -07:00
kgdb.c	sysrq, intel_fb: fix sysrq g collision	2009-05-15 07:56:24 -05:00
kmod.c	headers: mnt_namespace.h redux	2009-07-08 09:31:56 -07:00
kprobes.c	kprobes: Use kernel_text_address() for checking probe address	2009-07-30 16:44:06 -07:00
ksysfs.c
kthread.c	update the comment in kthread_stop()	2009-07-27 12:15:46 -07:00
latencytop.c
lockdep.c	Merge branch 'linus' into tracing/core	2009-05-07 11:17:34 +02:00
lockdep_internals.h	lockdep: increase MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS	2009-05-12 19:59:52 +02:00
lockdep_proc.c	lockdep: Fix file mode of lock_stat	2009-08-07 11:58:38 +02:00
lockdep_states.h
Makefile	Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-28 11:05:04 -07:00
marker.c
module.c	module: use MODULE_SYMBOL_PREFIX with module_layout	2009-07-27 12:15:45 -07:00
mutex-debug.c
mutex-debug.h
mutex.c	Merge branch 'linus' into perfcounters/core	2009-06-11 17:55:42 +02:00
mutex.h
notifier.c
ns_cgroup.c	cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups	2009-04-02 19:04:53 -07:00
nsproxy.c	nsproxy: extract create_nsproxy()	2009-06-18 13:03:56 -07:00
panic.c	trace: stop tracer in oops_enter()	2009-07-24 15:30:45 -04:00
params.c	module_param: allow 'bool' module_params to be bool, not just int.	2009-06-12 21:46:58 +09:30
perf_counter.c	perf_counter: Fix/complete ftrace event records sampling	2009-08-09 12:53:48 +02:00
pid.c	kmemleak: Remove alloc_bootmem annotations introduced in the past	2009-07-09 17:07:02 +01:00
pid_namespace.c	pidns: rewrite copy_pid_ns()	2009-06-18 13:03:55 -07:00
pm_qos_params.c
posix-cpu-timers.c	posix_cpu_timers_exit_group(): Do not use thread_group_cputimer()	2009-08-08 18:30:25 +02:00
posix-timers.c	posix-timers: Fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAW	2009-08-04 10:16:41 +02:00
printk.c	printk: Add KERN_DEFAULT printk log-level	2009-06-16 11:02:28 -07:00
profile.c	profile: suppress warning about large allocations when profile=1 is specified	2009-07-29 19:10:36 -07:00
ptrace.c	cred_guard_mutex: do not return -EINTR to user-space	2009-07-06 13:57:04 -07:00
rcuclassic.c	kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies	2009-04-03 12:23:02 +02:00
rcupdate.c	RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc	2009-04-15 13:55:14 -07:00
rcupreempt.c	rcu: rcu_sched_grace_period(): kill the bogus flush_signals()	2009-05-05 20:28:05 +02:00
rcupreempt_trace.c
rcutorture.c	cpumask: convert rcutorture.c	2009-03-30 22:05:16 +10:30
rcutree.c	rcu: Mark Hierarchical RCU no longer experimental	2009-06-24 15:02:48 +02:00
rcutree.h	kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies	2009-04-03 12:23:03 +02:00
rcutree_trace.c	rcu: Add __rcu_pending tracing to hierarchical RCU	2009-04-14 11:33:43 +02:00
relay.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
res_counter.c	memcg: add interface to reset limits	2009-06-18 13:03:48 -07:00
resource.c	kernel/resource.c: fix sign extension in reserve_setup()	2009-06-30 18:56:00 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()	2009-08-06 05:50:21 +02:00
rtmutex.h
rtmutex_common.h	rt_mutex: add proxy lock routines	2009-04-06 11:14:02 +02:00
rwsem.c
sched.c	sched: fix load average accounting vs. cpu hotplug	2009-07-18 14:19:52 +02:00
sched_clock.c	sched: Fix fallback sched_clock()'s offset when using jiffies	2009-05-09 10:08:19 +02:00
sched_cpupri.c	sched: Fix race in cpupri introduced by cpumask_var changes	2009-08-02 14:23:29 +02:00
sched_cpupri.h	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sched_debug.c	sched: Hide runqueues from direct refer at source code level	2009-06-17 18:29:42 +02:00
sched_fair.c	sched: Fix latencytop and sleep profiling vs group scheduling	2009-08-02 14:10:12 +02:00
sched_features.h	Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-03-30 17:17:35 -07:00
sched_idletask.c	sched, timers: move calc_load() to scheduler	2009-05-15 15:32:45 +02:00
sched_rt.c	sched_rt: Fix overload bug on rt group scheduling	2009-07-10 10:43:29 +02:00
sched_stats.h	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
seccomp.c	x86-64: seccomp: fix 32/64 syscall hole	2009-03-02 15:41:30 -08:00
semaphore.c
signal.c	do_sigaltstack: small cleanups	2009-08-01 11:18:56 -07:00
slow-work.c	slow-work: use round_jiffies() for thread pool's cull and OOM timers	2009-06-16 19:47:49 -07:00
smp.c	generic-ipi: fix hotplug_cfd()	2009-08-07 10:39:55 -07:00
softirq.c	softirq: introduce tasklet_hrtimer infrastructure	2009-07-22 17:01:17 +02:00
softlockup.c
spinlock.c	Allow rwlocks to re-enable interrupts	2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c
stop_machine.c	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sys.c	groups: move code to kernel/groups.c	2009-06-16 19:47:48 -07:00
sys_ni.c
sysctl.c	Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-28 11:05:28 -07:00
sysctl_check.c
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c	timer: Avoid reading uninitialized data	2009-07-18 23:11:43 +02:00
tracepoint.c	tracepoints: dont update zero-sized tracepoint sections	2009-03-18 19:55:00 +01:00
tsacct.c	Fix fixpoint divide exception in acct_update_integrals	2009-03-09 08:13:35 -07:00
uid16.c
up.c
user.c	sched: delayed cleanup of user_struct	2009-06-15 21:30:23 -07:00
user_namespace.c	Fix recursive lock in free_uid()/free_user_ns()	2009-02-27 16:26:21 -08:00
utsname.c	utsns: extract creeate_uts_ns()	2009-06-18 13:03:55 -07:00
utsname_sysctl.c	proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers	2009-04-02 19:05:01 -07:00
wait.c	wait: don't use __wake_up_common()	2009-04-14 17:17:16 +02:00
workqueue.c	ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro	2009-06-02 01:10:40 +02:00