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authorFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>2014-03-06 14:25:28 +0900
committerIngo Molnar <mingo@kernel.org>2014-03-11 11:33:48 +0100
commit96b3d28bf4b00f62fc8386ff5d487d1830793a3d (patch)
parent177c53d943368fc97644ebc0a250dc8e2d124250 (diff)
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>
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);
clock = sched_clock_local(scd);
- preempt_enable();
+ preempt_enable_notrace();
return clock;