linux/kernel
Tejun Heo 8a2e8e5dec workqueue: fix cwq->nr_active underflow
cwq->nr_active is used to keep track of how many work items are active
for the cpu workqueue, where 'active' is defined as either pending on
global worklist or executing.  This is used to implement the
max_active limit and workqueue freezing.  If a work item is queued
after nr_active has already reached max_active, the work item doesn't
increment nr_active and is put on the delayed queue and gets activated
later as previous active work items retire.

try_to_grab_pending() which is used in the cancellation path
unconditionally decremented nr_active whether the work item being
cancelled is currently active or delayed, so cancelling a delayed work
item makes nr_active underflow.  This breaks max_active enforcement
and triggers BUG_ON() in destroy_workqueue() later on.

This patch fixes this bug by adding a flag WORK_STRUCT_DELAYED, which
is set while a work item in on the delayed list and making
try_to_grab_pending() decrement nr_active iff the work item is
currently active.

The addition of the flag enlarges cwq alignment to 256 bytes which is
getting a bit too large.  It's scheduled to be reduced back to 128
bytes by merging WORK_STRUCT_PENDING and WORK_STRUCT_CWQ in the next
devel cycle.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
2010-08-25 10:33:56 +02:00
..
debug Merge branch 'timers-timekeeping-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 13:18:29 -07:00
gcov
irq irq: Add new IRQ flag IRQF_NO_SUSPEND 2010-07-29 13:24:57 +02:00
power Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block 2010-08-10 15:22:42 -07:00
time time: Workaround gcc loop optimization that causes 64bit div errors 2010-08-13 12:03:24 -07:00
trace block: add secure discard 2010-08-12 08:43:30 -07:00
.gitignore
acct.c pass a struct path to vfs_statfs 2010-08-09 16:48:42 -04:00
async.c async: use workqueue for worker pool 2010-07-14 11:29:46 +02:00
audit_tree.c fanotify: use both marks when possible 2010-07-28 10:18:55 -04:00
audit_watch.c Revert "fsnotify: store struct file not struct path" 2010-08-12 14:23:04 -07:00
audit.c Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify 2010-08-10 11:39:13 -07:00
audit.h Audit: split audit watch Kconfig 2010-07-28 09:58:19 -04:00
auditfilter.c audit: do not get and put just to free a watch 2010-07-28 09:58:17 -04:00
auditsc.c vfs: add helpers to get root and pwd 2010-08-11 00:28:20 -04:00
backtracetest.c
bounds.c kbuild: move bounds.h to include/generated 2009-12-12 13:08:14 +01:00
capability.c sched: Remove remaining USER_SCHED code 2010-04-02 20:12:00 +02:00
cgroup_freezer.c Freezer / cgroup freezer: Update stale locking comments 2010-05-10 23:18:47 +02:00
cgroup.c cgroups: save space for the terminator 2010-08-11 08:59:18 -07:00
compat.c rlimits: switch more rlimit syscalls to do_prlimit 2010-07-16 09:48:48 +02:00
configs.c
cpu.c sched: adjust when cpu_active and cpuset configurations are updated during cpu on/offlining 2010-06-08 21:40:36 +02:00
cpuset.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:39:22 -07:00
cred.c Add a dummy printk function for the maintenance of unused printks 2010-08-12 09:51:35 -07:00
delayacct.c
dma.c
early_res.c kmemleak: Add support for NO_BOOTMEM configurations 2010-07-19 11:54:15 +01:00
elfcore.c elf coredump: add extended numbering support 2010-03-06 11:26:46 -08:00
exec_domain.c sys_personality: remove the bogus checks in sys_personality()->__set_personality() path 2010-08-09 20:45:05 -07:00
exit.c ptrace: optimize exit_ptrace() for the likely case 2010-08-11 08:59:19 -07:00
extable.c
fork.c oom: badness heuristic rewrite 2010-08-09 20:45:02 -07:00
freezer.c
futex_compat.c futex: Protect pid lookup in compat code with RCU 2009-12-09 14:22:14 +01:00
futex.c futex: futex_find_get_task remove credentails check 2010-06-30 15:43:44 -07:00
groups.c security: remove dead hook task_setgroups 2010-04-12 12:19:18 +10:00
hrtimer.c Merge branch 'timers-timekeeping-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 13:18:29 -07:00
hung_task.c softlockup: Fix hung_task_check_count sysctl 2009-11-27 06:21:57 +01:00
hw_breakpoint.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:30:52 -07:00
itimer.c
kallsyms.c kdb: core for kgdb back end (2 of 2) 2010-05-20 21:04:21 -05:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks mutex: Better control mutex adaptive spinning config 2009-12-03 11:50:11 +01:00
Kconfig.preempt
kexec.c kexec: return -EFAULT on copy_to_user() failures 2010-08-11 08:59:22 -07:00
kfifo.c kernel/kfifo.c: add handling of chained scatterlists 2010-08-12 08:43:29 -07:00
kmod.c call_usermodehelper: UMH_WAIT_EXEC ignores kernel_thread() failure 2010-05-27 09:12:45 -07:00
kprobes.c kprobes: Move enable/disable_kprobe() out from debugfs code 2010-05-08 18:08:30 +02:00
ksysfs.c sysfs: add struct file* to bin_attr callbacks 2010-05-21 09:37:31 -07:00
kthread.c kthread: implement kthread_data() 2010-06-29 10:07:09 +02:00
latencytop.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
lockdep_internals.h lockdep: No need to disable preemption in debug atomic ops 2010-05-04 05:38:16 +02:00
lockdep_proc.c lockstat: Make lockstat counting per cpu 2010-04-06 00:15:37 +02:00
lockdep_states.h
lockdep.c sched_clock: Add local_clock() API and improve documentation 2010-06-09 10:34:49 +02:00
Makefile Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify 2010-08-10 11:39:13 -07:00
module.c module: cleanup comments, remove noinline 2010-08-05 12:59:13 +09:30
mutex-debug.c
mutex-debug.h locking: Implement new raw_spinlock 2009-12-14 23:55:32 +01:00
mutex.c mutex: Fix optimistic spinning vs. BKL 2010-05-19 08:18:44 +02:00
mutex.h
notifier.c sched: Use lockdep-based checking on rcu_dereference() 2010-02-25 10:34:26 +01:00
ns_cgroup.c
nsproxy.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
padata.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2010-08-04 15:23:14 -07:00
panic.c lib/bug.c: add oops end marker to WARN implementation 2010-08-11 08:59:22 -07:00
params.c param: locking for kernel parameters 2010-08-11 23:04:20 +09:30
perf_event.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:39:22 -07:00
pid_namespace.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pid.c pids: alloc_pidmap: remove the unnecessary boundary checks 2010-08-11 08:59:20 -07:00
pm_qos_params.c pm_qos: Get rid of the allocation in pm_qos_add_request() 2010-07-19 02:00:34 +02:00
posix-cpu-timers.c Merge branch 'writable_limits' of git://decibel.fi.muni.cz/~xslaby/linux 2010-08-10 12:07:51 -07:00
posix-timers.c posix_timer: Move copy_to_user(created_timer_id) down in timer_create() 2010-07-23 15:08:12 +02:00
printk.c gcc-4.6: printk: use stable variable to dump kmsg buffer 2010-08-09 20:45:06 -07:00
profile.c numa: in-kernel profiling: use cpu_to_mem() for per cpu allocations 2010-05-27 09:12:57 -07:00
ptrace.c ptrace: optimize exit_ptrace() for the likely case 2010-08-11 08:59:19 -07:00
range.c kernel/range: remove unused definition of ARRAY_SIZE() 2010-08-09 20:45:06 -07:00
rcupdate.c tree/tiny rcu: Add debug RCU head objects 2010-06-14 16:37:26 -07:00
rcutiny_plugin.h rcu: slim down rcutiny by removing rcu_scheduler_active and friends 2010-05-10 11:08:34 -07:00
rcutiny.c tree/tiny rcu: Add debug RCU head objects 2010-06-14 16:37:26 -07:00
rcutorture.c sched_clock: Add local_clock() API and improve documentation 2010-06-09 10:34:49 +02:00
rcutree_plugin.h rcu: remove all rcu head initializations, except on_stack initializations 2010-05-11 16:10:47 -07:00
rcutree_trace.c rcu: reduce the number of spurious RCU_SOFTIRQ invocations 2010-05-10 11:08:35 -07:00
rcutree.c tree/tiny rcu: Add debug RCU head objects 2010-06-14 16:37:26 -07:00
rcutree.h rcu: reduce the number of spurious RCU_SOFTIRQ invocations 2010-05-10 11:08:35 -07:00
relay.c kernel/: convert cpu notifier to return encapsulate errno value 2010-05-27 09:12:48 -07:00
res_counter.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
resource.c resource: shared I/O region support 2010-05-11 12:01:10 -07:00
rtmutex_common.h
rtmutex-debug.c sched: Convert pi_lock to raw_spinlock 2009-12-14 23:55:33 +01:00
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c rtmutes: Convert rtmutex.lock to raw_spinlock 2009-12-14 23:55:33 +01:00
rtmutex.h
rwsem.c
sched_clock.c sched_clock: Add local_clock() API and improve documentation 2010-06-09 10:34:49 +02:00
sched_cpupri.c sched: No need for bootmem special cases 2010-07-17 12:06:22 +02:00
sched_cpupri.h sched: No need for bootmem special cases 2010-07-17 12:06:22 +02:00
sched_debug.c sched: Use correct macro to display sched_child_runs_first in /proc/sched_debug 2010-07-21 21:46:12 +02:00
sched_fair.c Merge branch 'linus' into sched/core 2010-07-21 21:45:08 +02:00
sched_features.h sched: Remove ASYM_GRAN feature 2010-03-11 18:32:53 +01:00
sched_idletask.c sched: Cure load average vs NO_HZ woes 2010-04-23 11:02:02 +02:00
sched_rt.c sched: task_tick_rt: Remove the obsolete ->signal != NULL check 2010-06-18 10:46:56 +02:00
sched_stats.h sched: Remove the obsolete exit_state/signal hacks 2010-06-18 10:46:56 +02:00
sched.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:39:22 -07:00
seccomp.c
semaphore.c
signal.c CRED: Fix RCU warning due to previous patch fixing __task_cred()'s checks 2010-08-04 11:17:10 -07:00
smp.c kernel/: convert cpu notifier to return encapsulate errno value 2010-05-27 09:12:48 -07:00
softirq.c kernel/: fix BUG_ON checks for cpu notifier callbacks direct call 2010-06-04 15:21:45 -07:00
spinlock.c locking: Cleanup the name space completely 2009-12-14 23:55:33 +01:00
srcu.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
stacktrace.c
stop_machine.c stop_machine: struct cpu_stopper, remove alignment padding on 64 bits 2010-08-09 20:45:06 -07:00
sys_ni.c fanotify: sys_fanotify_mark declartion 2010-07-28 09:58:55 -04:00
sys.c rlimits: implement prlimit64 syscall 2010-07-16 09:48:48 +02:00
sysctl_binary.c sysctl: don't use own implementation of hex_to_bin() 2010-05-25 08:07:05 -07:00
sysctl_check.c ipv4 05/05: add sysctl to accept packets with local source addresses 2009-12-03 12:14:38 -08:00
sysctl.c Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify 2010-08-10 11:39:13 -07:00
taskstats.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
test_kprobes.c
time.c time: Kill off CONFIG_GENERIC_TIME 2010-07-27 12:40:54 +02:00
timeconst.pl
timer.c kernel/timer.c: fix kernel-doc function parameter warning 2010-08-10 15:33:09 -07:00
tracepoint.c tracing: Let tracepoints have data passed to tracepoint callbacks 2010-05-14 09:50:34 -04:00
tsacct.c mm: clean up mm_counter 2010-03-06 11:26:23 -08:00
uid16.c
up.c
user_namespace.c user_ns: Introduce user_nsmap_uid and user_ns_map_gid. 2010-06-16 14:55:34 -07:00
user-return-notifier.c core: Clean up user return notifers use of per_cpu 2009-12-02 10:22:59 +01:00
user.c sched: Remove a stale comment 2010-05-10 08:48:39 +02:00
utsname_sysctl.c
utsname.c
wait.c
watchdog.c kernel/watchdog: Initialize 'result' 2010-07-07 08:46:42 +02:00
workqueue_sched.h workqueue: implement concurrency managed dynamic worker pool 2010-06-29 10:07:14 +02:00
workqueue.c workqueue: fix cwq->nr_active underflow 2010-08-25 10:33:56 +02:00