linux/kernel
Kirill Tkhai 0f397f2c90 sched/dl: Fix race in dl_task_timer()
Throttled task is still on rq, and it may be moved to other cpu
if user is playing with sched_setaffinity(). Therefore, unlocked
task_rq() access makes the race.

Juri Lelli reports he got this race when dl_bandwidth_enabled()
was not set.

Other thing, pointed by Peter Zijlstra:

   "Now I suppose the problem can still actually happen when
    you change the root domain and trigger a effective affinity
    change that way".

To fix that we do the same as made in __task_rq_lock(). We do not
use __task_rq_lock() itself, because it has a useful lockdep check,
which is not correct in case of dl_task_timer(). We do not need
pi_lock locked here. This case is an exception (PeterZ):

   "The only reason we don't strictly need ->pi_lock now is because
    we're guaranteed to have p->state == TASK_RUNNING here and are
    thus free of ttwu races".

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/3056991400578422@web14g.yandex.ru
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05 11:51:12 +02:00
..
debug mm: per-thread vma caching 2014-04-07 16:35:53 -07:00
events Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2014-04-05 13:20:43 -07:00
gcov
irq
locking Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-16 16:35:18 -07:00
power kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
printk printk: fix one circular lockdep warning about console_lock 2014-04-03 16:21:08 -07:00
rcu Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-03-31 11:21:19 -07:00
sched sched/dl: Fix race in dl_task_timer() 2014-06-05 11:51:12 +02:00
time tick-sched: Check tick_nohz_enabled in tick_nohz_switch_to_nohz() 2014-04-15 20:26:58 +02:00
trace This contains two fixes. 2014-04-18 10:16:43 -07:00
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
Makefile Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-03-31 14:13:25 -07:00
acct.c
async.c
audit.c Merge git://git.infradead.org/users/eparis/audit 2014-04-12 12:38:53 -07:00
audit.h
audit_tree.c
audit_watch.c
auditfilter.c Merge git://git.infradead.org/users/eparis/audit 2014-04-12 12:38:53 -07:00
auditsc.c Merge git://git.infradead.org/users/eparis/audit 2014-04-12 12:38:53 -07:00
backtracetest.c
bounds.c
capability.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2014-04-03 09:26:18 -07:00
cgroup.c cgroup: newly created dirs and files should be owned by the creator 2014-04-07 16:44:47 -04:00
cgroup_freezer.c
compat.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-02 12:51:41 -07:00
configs.c
context_tracking.c
cpu.c sched: Fix hotplug vs. set_cpus_allowed_ptr() 2014-05-22 10:21:31 +02:00
cpu_pm.c
cpuset.c Merge branch 'akpm' (incoming from Andrew) 2014-04-03 16:22:16 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c wait: WSTOPPED|WCONTINUED doesn't work if a zombie leader is traced by another process 2014-04-07 16:36:06 -07:00
extable.c
fork.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
freezer.c
futex.c futex: update documentation for ordering guarantees 2014-04-12 17:57:51 -07:00
futex_compat.c
groups.c kernel/groups.c: remove return value of set_groups 2014-04-03 16:21:05 -07:00
hrtimer.c
hung_task.c kernel: audit/fix non-modular users of module_init in core code 2014-04-03 16:21:07 -07:00
irq_work.c
itimer.c
jump_label.c
kallsyms.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
kcmp.c
kexec.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
kmod.c
kprobes.c
ksysfs.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
kthread.c kthread: ensure locality of task_struct allocations 2014-04-03 16:20:49 -07:00
latencytop.c
module-internal.h
module.c modules: use raw_cpu_write for initialization of per cpu refcount. 2014-04-07 16:36:14 -07:00
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c kernel/panic.c: display reason at end + pr_emerg 2014-04-07 16:36:08 -07:00
params.c
pid.c
pid_namespace.c pid_namespace: pidns_get() should check task_active_pid_ns() != NULL 2014-04-02 16:20:21 -07:00
posix-cpu-timers.c
posix-timers.c
profile.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
ptrace.c
range.c
reboot.c
relay.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
res_counter.c res_counter: remove interface for locked charging and uncharging 2014-04-07 16:35:54 -07:00
resource.c kernel/resource.c: make reallocate_resource() static 2014-04-03 16:21:07 -07:00
seccomp.c seccomp: fix memory leak on filter attach 2014-04-16 15:25:53 -04:00
signal.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys.c mm, thp: add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE 2014-04-07 16:35:52 -07:00
sys_ni.c fs, kernel: permit disabling the uselib syscall 2014-04-03 16:21:05 -07:00
sysctl.c hung_task: check the value of "sysctl_hung_task_timeout_sec" 2014-04-07 16:36:07 -07:00
sysctl_binary.c
system_certificates.S
system_keyring.c
task_work.c
taskstats.c
test_kprobes.c
time.c
timeconst.bc
timer.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-01 11:00:07 -07:00
torture.c
tracepoint.c This includes the final patch to clean up and fix the issue with the 2014-04-12 13:06:10 -07:00
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c kernel: audit/fix non-modular users of module_init in core code 2014-04-03 16:21:07 -07:00
user_namespace.c user namespace: fix incorrect memory barriers 2014-04-14 16:03:02 -07:00
utsname.c
utsname_sysctl.c
watchdog.c kernel/watchdog.c:touch_softlockup_watchdog(): use raw_cpu_write() 2014-04-18 16:40:08 -07:00
workqueue.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-01 11:00:07 -07:00
workqueue_internal.h