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| author | Wanpeng Li <wanpeng.li@hotmail.com> | 2017-07-09 00:40:28 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-14 10:27:15 +0200 |
| commit | 0e4097c3354e2f5a5ad8affd9dc7f7f7d00bb6b9 (patch) | |
| tree | 7806ceddfe0be9927e01527f5db610310bdbd71a | |
| parent | 242fc35290bd8cf0effc6e3474e3a417985de2f3 (diff) | |
| download | linux-0e4097c3354e2f5a5ad8affd9dc7f7f7d00bb6b9.tar.bz2 | |
sched/cputime: Don't use smp_processor_id() in preemptible context
Recent kernels trigger this warning:
BUG: using smp_processor_id() in preemptible [00000000] code: 99-trinity/181
caller is debug_smp_processor_id+0x17/0x19
CPU: 0 PID: 181 Comm: 99-trinity Not tainted 4.12.0-01059-g2a42eb9 #1
Call Trace:
dump_stack+0x82/0xb8
check_preemption_disabled()
debug_smp_processor_id()
vtime_delta()
task_cputime()
thread_group_cputime()
thread_group_cputime_adjusted()
wait_consider_task()
do_wait()
SYSC_wait4()
do_syscall_64()
entry_SYSCALL64_slow_path()
As Frederic pointed out:
| Although those sched_clock_cpu() things seem to only matter when the
| sched_clock() is unstable. And that stability is a condition for nohz_full
| to work anyway. So probably sched_clock() alone would be enough.
This patch fixes it by replacing sched_clock_cpu() with sched_clock() to
avoid calling smp_processor_id() in a preemptible context.
Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1499586028-7402-1-git-send-email-wanpeng.li@hotmail.com
[ Prettified the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/sched/cputime.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 6e3ea4ac1bda..14d2dbf97c53 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -683,7 +683,7 @@ static u64 vtime_delta(struct vtime *vtime) { unsigned long long clock; - clock = sched_clock_cpu(smp_processor_id()); + clock = sched_clock(); if (clock < vtime->starttime) return 0; @@ -814,7 +814,7 @@ void arch_vtime_task_switch(struct task_struct *prev) write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; - vtime->starttime = sched_clock_cpu(smp_processor_id()); + vtime->starttime = sched_clock(); write_seqcount_end(&vtime->seqcount); } @@ -826,7 +826,7 @@ void vtime_init_idle(struct task_struct *t, int cpu) local_irq_save(flags); write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; - vtime->starttime = sched_clock_cpu(cpu); + vtime->starttime = sched_clock(); write_seqcount_end(&vtime->seqcount); local_irq_restore(flags); } |