diff options
| author | Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> | 2014-03-06 06:25:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-03-11 11:33:48 +0100 |
| commit | 96b3d28bf4b00f62fc8386ff5d487d1830793a3d (patch) | |
| tree | 3e5f3fbd1ac4b194d10e3cda56a6640d3658adcb /kernel/sched/clock.c | |
| parent | stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus() (diff) | |
| download | linux-96b3d28bf4b00f62fc8386ff5d487d1830793a3d.tar.xz linux-96b3d28bf4b00f62fc8386ff5d487d1830793a3d.zip | |
sched/clock: Prevent tracing recursion in sched_clock_cpu()
Prevent tracing of preempt_disable/enable() in sched_clock_cpu().
When CONFIG_DEBUG_PREEMPT is enabled, preempt_disable/enable() are
traced and this causes trace_clock() users (and probably others) to
go into an infinite recursion. Systems with a stable sched_clock()
are not affected.
This problem is similar to that fixed by upstream commit 95ef1e52922
("KVM guest: prevent tracing recursion with kvmclock").
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1394083528.4524.3.camel@nexus
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/clock.c')
| -rw-r--r-- | kernel/sched/clock.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 43c2bcc35761..b30a2924ef14 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -301,14 +301,14 @@ u64 sched_clock_cpu(int cpu) if (unlikely(!sched_clock_running)) return 0ull; - preempt_disable(); + preempt_disable_notrace(); scd = cpu_sdc(cpu); if (cpu != smp_processor_id()) clock = sched_clock_remote(scd); else clock = sched_clock_local(scd); - preempt_enable(); + preempt_enable_notrace(); return clock; } |