sched/clock: Prevent tracing recursion in sched_clock_cpu()
authorFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Thu, 6 Mar 2014 05:25:28 +0000 (14:25 +0900)
committerIngo Molnar <mingo@kernel.org>
Tue, 11 Mar 2014 10:33:48 +0000 (11:33 +0100)
commit96b3d28bf4b00f62fc8386ff5d487d1830793a3d
tree3e5f3fbd1ac4b194d10e3cda56a6640d3658adcb
parent177c53d943368fc97644ebc0a250dc8e2d124250
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>
kernel/sched/clock.c