Re: [PATCH] sched/clock: prevent tracing recursion in sched_clock_cpu()

From: Fernando Luis VÃzquez Cao
Date: Mon Mar 10 2014 - 03:18:26 EST


On 03/06/2014 07:51 PM, Steven Rostedt wrote:
On Thu, 06 Mar 2014 14:25:28 +0900
Fernando Luis VÃzquez Cao <fernando_b1@xxxxxxxxxxxxx> wrote:

From: Fernando Luis Vazquez Cao <fernando@xxxxxxxxxxxxx>

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 <rostedt@xxxxxxxxxxx>

Thank you four your review, Peter, Steven.

By the way, who is going to pick this patch? Do you want
me to resend with Steven's Acked-by added?

- Fernando
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