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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2014-12-25 15:51:21 +0900
committerIngo Molnar <mingo@kernel.org>2015-01-09 11:19:00 +0100
commit7f1a169b88f513e32a432ca0f85bfd282d117bd6 (patch)
treed1d643a4b9852f42a277392aa2c814428c09e959
parent269ad8015a6b2bb1cf9e684da4921eb6fa0a0c88 (diff)
sched/fair: Fix RCU stall upon -ENOMEM in sched_create_group()
When alloc_fair_sched_group() in sched_create_group() fails, free_sched_group() is called, and free_fair_sched_group() is called by free_sched_group(). Since destroy_cfs_bandwidth() is called by free_fair_sched_group() without calling init_cfs_bandwidth(), RCU stall occurs at hrtimer_cancel(): INFO: rcu_sched self-detected stall on CPU { 1} (t=60000 jiffies g=13074 c=13073 q=0) Task dump for CPU 1: (fprintd) R running task 0 6249 1 0x00000088 ... Call Trace: <IRQ> [<ffffffff81094988>] sched_show_task+0xa8/0x110 [<ffffffff81097acd>] dump_cpu_task+0x3d/0x50 [<ffffffff810c3a80>] rcu_dump_cpu_stacks+0x90/0xd0 [<ffffffff810c7751>] rcu_check_callbacks+0x491/0x700 [<ffffffff810cbf2b>] update_process_times+0x4b/0x80 [<ffffffff810db046>] tick_sched_handle.isra.20+0x36/0x50 [<ffffffff810db0a2>] tick_sched_timer+0x42/0x70 [<ffffffff810ccb19>] __run_hrtimer+0x69/0x1a0 [<ffffffff810db060>] ? tick_sched_handle.isra.20+0x50/0x50 [<ffffffff810ccedf>] hrtimer_interrupt+0xef/0x230 [<ffffffff810452cb>] local_apic_timer_interrupt+0x3b/0x70 [<ffffffff8164a465>] smp_apic_timer_interrupt+0x45/0x60 [<ffffffff816485bd>] apic_timer_interrupt+0x6d/0x80 <EOI> [<ffffffff810cc588>] ? lock_hrtimer_base.isra.23+0x18/0x50 [<ffffffff81193cf1>] ? __kmalloc+0x211/0x230 [<ffffffff810cc9d2>] hrtimer_try_to_cancel+0x22/0xd0 [<ffffffff81193cf1>] ? __kmalloc+0x211/0x230 [<ffffffff810ccaa2>] hrtimer_cancel+0x22/0x30 [<ffffffff810a3cb5>] free_fair_sched_group+0x25/0xd0 [<ffffffff8108df46>] free_sched_group+0x16/0x40 [<ffffffff810971bb>] sched_create_group+0x4b/0x80 [<ffffffff810aa383>] sched_autogroup_create_attach+0x43/0x1c0 [<ffffffff8107dc9c>] sys_setsid+0x7c/0x110 [<ffffffff81647729>] system_call_fastpath+0x12/0x17 Check whether init_cfs_bandwidth() was called before calling destroy_cfs_bandwidth(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> [ Move the check into destroy_cfs_bandwidth() to aid compilability. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Paul Turner <pjt@google.com> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/201412252210.GCC30204.SOMVFFOtQJFLOH@I-love.SAKURA.ne.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/fair.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6b99659cbeec..40667cbf371b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4005,6 +4005,10 @@ void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b, bool force)
static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
{
+ /* init_cfs_bandwidth() was not called */
+ if (!cfs_b->throttled_cfs_rq.next)
+ return;
+
hrtimer_cancel(&cfs_b->period_timer);
hrtimer_cancel(&cfs_b->slack_timer);
}