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Oleg Nesterov 13c22168b7 destroy_workqueue() can livelock 
Pointed out by Michal Schmidt <mschmidt@redhat.com>.

The bug was introduced in 2.6.22 by me.

cleanup_workqueue_thread() does flush_cpu_workqueue(cwq) in a loop until
->worklist becomes empty.  This is live-lockable, a re-niced caller can get
CPU after wake_up() and insert a new barrier before the lower-priority
cwq->thread has a chance to clear ->current_work.

Change cleanup_workqueue_thread() to do flush_cpu_workqueue(cwq) only once.
 We can rely on the fact that run_workqueue() won't return until it flushes
all works.  So it is safe to call kthread_stop() after that, the "should
stop" request won't be noticed until run_workqueue() returns.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:03 -07:00
..
irq Improve behaviour of spurious IRQ detect 2007-07-16 09:05:46 -07:00
power PM: introduce set_target method in pm_ops 2007-07-01 12:29:44 -07:00
time kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
.gitignore
acct.c [PATCH] kernel: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:42 -08:00
audit.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
audit.h Audit: add TTY input auditing 2007-07-16 09:05:47 -07:00
auditfilter.c audit: fix oops removing watch if audit disabled 2007-06-24 08:59:12 -07:00
auditsc.c kerneldoc fix in audit_core_dumps 2007-07-16 09:05:48 -07:00
capability.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
compat.c signal/timer/event: timerfd compat code 2007-05-11 08:29:36 -07:00
configs.c use simple_read_from_buffer in kernel/ 2007-05-09 12:30:49 -07:00
cpu.c microcode: use suspend-related CPU hotplug notifications 2007-05-09 12:30:56 -07:00
cpuset.c Reduce cpuset.c write_lock_irq() to read_lock() 2007-07-16 09:05:43 -07:00
delayacct.c sched: update delay-accounting to use CFS's precise stats 2007-07-09 18:52:00 +02:00
die_notifier.c move die notifier handling to common code 2007-05-08 11:15:04 -07:00
dma.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
exec_domain.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
exit.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
extable.c [PATCH] symbol_put_addr() locks kernel 2006-05-15 11:20:55 -07:00
fork.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
futex_compat.c Revert "futex_requeue_pi optimization" 2007-06-18 09:48:41 -07:00
futex.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
hrtimer.c [HRTIMER] Fix cpu pointer arg to clockevents_notify() 2007-07-16 17:29:56 -07:00
itimer.c The scheduled -EINVAL for invalid timevals in setitimer 2007-05-08 11:15:13 -07:00
kallsyms.c kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
Kconfig.hz [PATCH] HZ: 300Hz support 2006-12-07 08:39:36 -08:00
Kconfig.preempt Fix trivial typos in Kconfig* files 2007-05-09 07:12:20 +02:00
kexec.c kdump/kexec: calculate note size at compile time 2007-05-08 11:15:07 -07:00
kfifo.c is_power_of_2: kernel/kfifo.c 2007-07-16 09:05:50 -07:00
kmod.c wait_for_helper: remove unneeded do_sigaction() 2007-05-09 12:30:53 -07:00
kprobes.c Kprobes: The ON/OFF knob thru debugfs 2007-05-08 11:15:19 -07:00
ksysfs.c remove "struct subsystem" as it is no longer needed 2007-05-02 18:57:59 -07:00
kthread.c mm: fix improper .init-type section references 2007-07-16 09:05:36 -07:00
latency.c [PATCH] severing module.h->sched.h 2006-12-04 02:00:22 -05:00
lockdep_internals.h [PATCH] lockdep: more chains 2006-12-07 08:39:43 -08:00
lockdep_proc.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
lockdep.c kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
Makefile user namespace: add the framework 2007-07-16 09:05:47 -07:00
module.c kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
mutex-debug.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
mutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
mutex.c wrap access to thread_info 2007-05-09 12:30:56 -07:00
mutex.h [PATCH] lockdep: prove mutex locking correctness 2006-07-03 15:27:04 -07:00
nsproxy.c namespace: ensure clone_flags are always stored in an unsigned long 2007-07-16 09:05:48 -07:00
panic.c Report that kernel is tainted if there was an OOPS 2007-07-17 10:23:02 -07:00
params.c sysfs: kill unnecessary attribute->owner 2007-07-11 16:09:06 -07:00
pid.c namespace: ensure clone_flags are always stored in an unsigned long 2007-07-16 09:05:48 -07:00
posix-cpu-timers.c sched: make posix-cpu-timers use CFS's accounting information 2007-07-09 18:51:58 +02:00
posix-timers.c posix-timers: Prevent softirq starvation by small intervals and SIG_IGN 2007-06-21 15:57:04 -07:00
printk.c kernel/printk.c: document possible deadlock against scheduler 2007-07-16 09:05:52 -07:00
profile.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
ptrace.c PTRACE_POKEDATA consolidation 2007-07-17 10:23:03 -07:00
rcupdate.c Add suspend-related notifications for CPU hotplug 2007-05-09 12:30:56 -07:00
rcutorture.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
relay.c relay: fixup kerneldoc comment 2007-07-13 14:14:28 +02:00
resource.c libata/IDE: remove combined mode quirk 2007-04-28 14:15:59 -04:00
rtmutex_common.h FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex-debug.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rtmutex-tester.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
rtmutex.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rwsem.c Lockdep treats down_write_trylock like regular down_write 2007-05-08 11:15:09 -07:00
sched_debug.c [PATCH] sched: remove stale version info from kernel/sched_debug.c 2007-07-13 10:10:41 -07:00
sched_fair.c sched: cfs core, kernel/sched_fair.c 2007-07-09 18:51:58 +02:00
sched_idletask.c sched: cfs core, kernel/sched_idletask.c 2007-07-09 18:51:58 +02:00
sched_rt.c sched: cfs core, kernel/sched_rt.c 2007-07-09 18:51:58 +02:00
sched_stats.h sched: update delay-accounting to use CFS's precise stats 2007-07-09 18:52:00 +02:00
sched.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
seccomp.c make seccomp zerocost in schedule 2007-07-16 09:05:50 -07:00
signal.c vdso: print fatal signals 2007-07-16 09:05:43 -07:00
softirq.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
softlockup.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
spinlock.c [PATCH] lockdep: spin_lock_irqsave_nested() 2006-11-25 13:28:34 -08:00
srcu.c [PATCH] SRCU: report out-of-memory errors 2006-10-04 07:55:30 -07:00
stacktrace.c [PATCH] lockdep: stacktrace subsystem, core 2006-07-03 15:27:02 -07:00
stop_machine.c Fix stop_machine_run problem with naughty real time process 2007-07-16 09:05:41 -07:00
sys_ni.c diskquota: 32bit quota tools on 64bit architectures 2007-07-16 09:05:48 -07:00
sys.c move seccomp from /proc to a prctl 2007-07-16 09:05:50 -07:00
sysctl.c proper prototype for proc_nr_files() 2007-07-17 10:23:03 -07:00
taskstats.c taskstats: add context-switch counters 2007-07-16 09:05:46 -07:00
time.c sys_time() speedup 2007-07-16 09:05:48 -07:00
timer.c Slab allocators: Replace explicit zeroing with __GFP_ZERO 2007-07-17 10:23:02 -07:00
tsacct.c [PATCH] time: x86_64: split x86_64/kernel/time.c up 2007-02-16 08:14:00 -08:00
uid16.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
user_namespace.c fix create_new_namespaces() return value 2007-07-16 09:05:47 -07:00
user.c user namespace: add the framework 2007-07-16 09:05:47 -07:00
utsname_sysctl.c remove CONFIG_UTS_NS and CONFIG_IPC_NS 2007-07-16 09:05:47 -07:00
utsname.c namespace: ensure clone_flags are always stored in an unsigned long 2007-07-16 09:05:48 -07:00
wait.c Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
workqueue.c destroy_workqueue() can livelock 2007-07-17 10:23:03 -07:00