Tejun Heo 6ff96f7340 workqueue: cond_resched() after processing each work item ... commit b22ce2785d upstream. If !PREEMPT, a kworker running work items back to back can hog CPU. This becomes dangerous when a self-requeueing work item which is waiting for something to happen races against stop_machine. Such self-requeueing work item would requeue itself indefinitely hogging the kworker and CPU it's running on while stop_machine would wait for that CPU to enter stop_machine while preventing anything else from happening on all other CPUs. The two would deadlock. Jamie Liu reports that this deadlock scenario exists around scsi_requeue_run_queue() and libata port multiplier support, where one port may exclude command processing from other ports. With the right timing, scsi_requeue_run_queue() can end up requeueing itself trying to execute an IO which is asked to be retried while another device has an exclusive access, which in turn can't make forward progress due to stop_machine. Fix it by invoking cond_resched() after executing each work item. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jamie Liu <jamieliu@google.com> References: http://thread.gmane.org/gmane.linux.kernel/1552567 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-09-07 22:09:58 -07:00
..
cpu	idle: Enable interrupts in the weak arch_cpu_idle() implementation	2013-06-14 23:01:05 +02:00
debug	kgdb/sysrq: fix inconstistent help message of sysrq key	2013-04-30 17:04:10 -07:00
events	perf: Fix perf_lock_task_context() vs RCU	2013-07-25 14:07:43 -07:00
gcov
irq	genirq: Fix can_request_irq() for IRQs without an action	2013-07-21 18:21:27 -07:00
power	PM / QoS: Fix workqueue deadlock when using pm_qos_update_request_timeout()	2013-08-20 08:43:05 -07:00
sched	sched: Ensure update_cfs_shares() is called for parents of continuously-running tasks	2013-08-20 08:43:02 -07:00
time	timer_list: correct the iterator for timer_list	2013-09-07 22:09:58 -07:00
trace	ftrace: Check module functions being traced on reload	2013-08-29 09:47:34 -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_tree.c	kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules()	2013-06-12 16:29:46 -07:00
audit_watch.c
audit.c	audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE	2013-06-12 16:29:45 -07:00
audit.h	Merge git://git.infradead.org/users/eparis/audit	2013-05-11 14:29:11 -07:00
auditfilter.c	auditfilter.c: fix kernel-doc warnings	2013-05-24 16:22:52 -07:00
auditsc.c	audit: Make testing for a valid loginuid explicit.	2013-05-07 22:27:15 -04:00
backtracetest.c
bounds.c
capability.c	Add file_ns_capable() helper function for open-time capability checking	2013-04-14 10:06:31 -07:00
cgroup_freezer.c
cgroup.c	cgroup: fix umount vs cgroup_cfts_commit() race	2013-08-11 18:35:24 -07:00
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_pm.c
cpu.c	CPU hotplug: provide a generic helper to disable/enable CPU hotplug	2013-06-12 16:29:44 -07:00
cpuset.c	cpuset: fix the return value of cpuset_write_u64()	2013-08-20 08:43:05 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	move exit_task_namespaces() outside of exit_notify()	2013-06-15 05:39:08 +04:00
extable.c	extable: Flip the sorting message	2013-04-15 13:25:16 +02:00
fork.c	microblaze: fix clone syscall	2013-08-20 08:43:02 -07:00
freezer.c
futex_compat.c
futex.c	futex: Take hugepages into account when generating futex_key	2013-07-13 11:42:26 -07:00
groups.c
hrtimer.c	hrtimers: Move SMP function call to thread context	2013-07-28 16:30:22 -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
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kexec: Use min() and min_t() to simplify logic	2013-04-30 17:04:07 -07:00
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_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c	Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block	2013-05-08 11:51:05 -07:00
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_signing.c
module-internal.h
module.c	module: do percpu allocation after uniqueness check. No, really!	2013-07-13 11:42:26 -07:00
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_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -07:00
pid.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -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: Remove unused variable	2013-04-18 12:51:19 +02:00
printk.c	printk: Fix rq->lock vs logbuf_lock unlock lock inversion	2013-07-25 14:07:31 -07:00
profile.c	proc: Supply PDE attribute setting accessor functions	2013-05-01 17:29:18 -04:00
ptrace.c	Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation	2013-06-29 11:29:08 -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_plugin.h
rcutiny.c
rcutorture.c
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
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
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_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c	locking/rtmutex/tester: Set correct permissions on sysfs files	2013-04-10 14:48:37 +02:00
rtmutex.c
rtmutex.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	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2013-05-01 14:08:52 -07:00
smp.c	kernel/smp.c: cleanups	2013-04-30 17:04:03 -07:00
smpboot.c	kthread: Prevent unpark race which puts threads on the wrong cpu	2013-04-12 14:18:43 +02:00
smpboot.h
softirq.c	Fix lockup related to stop_machine being stuck in __do_softirq.	2013-06-10 17:46:57 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c	unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE	2013-05-09 13:46:38 -04:00
sys.c	reboot: rigrate shutdown/reboot to boot cpu	2013-06-12 16:29:44 -07:00
sysctl_binary.c	switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE	2013-05-09 14:53:20 -04:00
sysctl.c	mm: replace hardcoded 3% with admin_reserve_pages knob	2013-04-29 15:54:36 -07:00
task_work.c
taskstats.c
test_kprobes.c	kernel/: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
time.c
timeconst.bc
timer.c	timer: Fix jiffies wrap behavior of round_jiffies_common()	2013-07-21 18:21:31 -07:00
tracepoint.c	Tracing updates for Linux 3.10	2013-04-29 13:55:38 -07:00
tsacct.c
uid16.c
up.c
user_namespace.c	userns: limit the maximum depth of user_namespace->parent chain	2013-08-11 18:35:25 -07:00
user-return-notifier.c
user.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -07:00
utsname_sysctl.c
utsname.c	proc: Split the namespace stuff out into linux/proc_ns.h	2013-05-01 17:29:39 -04:00
wait.c
watchdog.c
workqueue_internal.h	workqueue: include workqueue info when printing debug dump of a worker task	2013-04-30 17:04:02 -07:00
workqueue.c	workqueue: cond_resched() after processing each work item	2013-09-07 22:09:58 -07:00