On Thu, 06 Mar 2014 14:25:28 +0900 Fernando Luis Vázquez Cao <[email protected]> wrote:
> From: Fernando Luis Vazquez Cao <[email protected]> > > 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"). Also similar to: 569d6557ab957. Acked-by: Steven Rostedt <[email protected]> -- Steve > > Cc: Linus Torvalds <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Steven Rostedt <[email protected]> > Signed-off-by: Fernando Luis Vazquez Cao <[email protected]> > --- > > diff -urNp linux-3.14-rc5-orig/kernel/sched/clock.c > linux-3.14-rc5/kernel/sched/clock.c > --- linux-3.14-rc5-orig/kernel/sched/clock.c 2014-03-06 13:37:43.567720550 > +0900 > +++ linux-3.14-rc5/kernel/sched/clock.c 2014-03-06 13:41:56.937100949 > +0900 > @@ -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; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
