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| author | Li Zhong <zhong@linux.vnet.ibm.com> | 2013-04-28 11:25:58 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-04-29 13:17:33 +0200 |
| commit | 6296ace467c8640317414ba589b124323806f7ce (patch) | |
| tree | 0bff9b94a366b77ad622f20aa2c85ae435e35e77 /kernel | |
| parent | a1412ec539e4025831777ef78a1ce427c97bf400 (diff) | |
| download | op-kernel-dev-6296ace467c8640317414ba589b124323806f7ce.zip op-kernel-dev-6296ace467c8640317414ba589b124323806f7ce.tar.gz | |
nohz: Protect smp_processor_id() in tick_nohz_task_switch()
I saw following error when testing the latest nohz code on
Power:
[ 85.295384] BUG: using smp_processor_id() in preemptible [00000000] code: rsyslogd/3493
[ 85.295396] caller is .tick_nohz_task_switch+0x1c/0xb8
[ 85.295402] Call Trace:
[ 85.295408] [c0000001fababab0] [c000000000012dc4] .show_stack+0x110/0x25c (unreliable)
[ 85.295420] [c0000001fababba0] [c0000000007c4b54] .dump_stack+0x20/0x30
[ 85.295430] [c0000001fababc10] [c00000000044eb74] .debug_smp_processor_id+0xf4/0x124
[ 85.295438] [c0000001fababca0] [c0000000000d7594] .tick_nohz_task_switch+0x1c/0xb8
[ 85.295447] [c0000001fababd20] [c0000000000b9748] .finish_task_switch+0x13c/0x160
[ 85.295455] [c0000001fababdb0] [c0000000000bbe50] .schedule_tail+0x50/0x124
[ 85.295463] [c0000001fababe30] [c000000000009dc8] .ret_from_fork+0x4/0x54
The code below moves the test into local_irq_save/restore
section to avoid the above complaint.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1367119558.6391.34.camel@ThinkPad-T5421.cn.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/tick-sched.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index da53c8f..1c9f53b 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -251,14 +251,15 @@ void tick_nohz_task_switch(struct task_struct *tsk) { unsigned long flags; - if (!tick_nohz_full_cpu(smp_processor_id())) - return; - local_irq_save(flags); + if (!tick_nohz_full_cpu(smp_processor_id())) + goto out; + if (tick_nohz_tick_stopped() && !can_stop_full_tick()) tick_nohz_full_kick(); +out: local_irq_restore(flags); } |
