Li Zefan 4729583006 cpuset: fix a locking issue in cpuset_migrate_mm() ... I can trigger a lockdep warning: # mount -t cgroup -o cpuset xxx /cgroup # mkdir /cgroup/cpuset # mkdir /cgroup/tmp # echo 0 > /cgroup/tmp/cpuset.cpus # echo 0 > /cgroup/tmp/cpuset.mems # echo 1 > /cgroup/tmp/cpuset.memory_migrate # echo $$ > /cgroup/tmp/tasks # echo 1 > /cgruop/tmp/cpuset.mems =============================== [ INFO: suspicious RCU usage. ] 3.14.0-rc1-0.1-default+ #32 Not tainted ------------------------------- include/linux/cgroup.h:682 suspicious rcu_dereference_check() usage! ... [<ffffffff81582174>] dump_stack+0x72/0x86 [<ffffffff810b8f01>] lockdep_rcu_suspicious+0x101/0x140 [<ffffffff81105ba1>] cpuset_migrate_mm+0xb1/0xe0 ... We used to hold cgroup_mutex when calling cpuset_migrate_mm(), but now we hold cpuset_mutex, which causes task_css() to complain. This is not a false-positive but a real issue. Holding cpuset_mutex won't prevent a task from migrating to another cpuset, and it won't prevent the original task->cgroup from destroying during this change. Fixes: 5d21cc2db0 (cpuset: replace cgroup_mutex locking with cpuset internal locking) Cc: <stable@vger.kernel.org> # 3.9+ Signed-off-by: Li Zefan <lizefan@huawei.com> Sigend-off-by: Tejun Heo <tj@kernel.org>		2014-02-27 09:35:59 -05:00
..
cpu
debug
events
gcov
irq
locking
power	arm, pm, vmpressure: add missing slab.h includes	2014-02-03 13:24:01 -05:00
printk
rcu
sched	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 09:02:51 -08:00
time
trace
.gitignore
acct.c
async.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c	cgroup: update cgroup_enable_task_cg_lists() to grab siglock	2014-02-18 18:23:18 -05:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c
cpuset.c	cpuset: fix a locking issue in cpuset_migrate_mm()	2014-02-27 09:35:59 -05:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c
fork.c
freezer.c
futex_compat.c
futex.c
groups.c
hrtimer.c
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
module_signing.c
module-internal.h
module.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c
posix-cpu-timers.c
posix-timers.c
profile.c
ptrace.c
range.c
reboot.c
relay.c
res_counter.c
resource.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 09:02:51 -08:00
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl_binary.c
sysctl.c	Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 08:59:46 -08:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c
test_kprobes.c
time.c
timeconst.bc
timer.c
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c
workqueue_internal.h
workqueue.c