From: Li Yi <yi.li@analog.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org,
uclinux-dist-devel@blackfin.uclinux.org
Subject: Re: [PATCH] Ftrace: irqsoff tracer may cause stack overflow
Date: Fri, 8 Jan 2010 17:13:15 +0800 [thread overview]
Message-ID: <1262941995.27700.282.camel@adam-desktop> (raw)
In-Reply-To: <20100108051847.GB5468@nowhere>
On Fri, 2010-01-08 at 06:18 +0100, Frederic Weisbecker wrote:
> On Fri, Jan 08, 2010 at 12:45:25PM +0800, Li Yi wrote:
> > "irqsoff" tracer may cause stack overflow on architectures using
> > asm-generic/atomic.h, due to recursive invoking of, e.g.
> > trace_hardirqs_off().
> >
> > trace_hardirqs_off() -> start_critical_timing() -> atomic_inc() ->
> > atomic_add_return() -> local_irq_save() -> trace_hardirqs_off()
> >
> > Signed-off-by: Yi Li <yi.li@analog.com>
>
>
>
> Good catch!
>
> However, may be we should keep the local_irq_save there
> and have __raw_atomic_* versions only for tracing.
>
> It's better to keep track of most irq disabled sites.
>
> Why not something like the following (untested):
Yes. I agree this is better solution.
-Yi
next prev parent reply other threads:[~2010-01-08 9:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-08 4:45 [PATCH] Ftrace: irqsoff tracer may cause stack overflow Li Yi
2010-01-08 4:54 ` Mike Frysinger
2010-01-08 6:26 ` Li Yi
2010-01-08 6:26 ` Mike Frysinger
2010-01-08 5:18 ` Frederic Weisbecker
2010-01-08 9:13 ` Li Yi [this message]
2010-01-08 15:22 ` Steven Rostedt
2010-01-08 18:27 ` Frederic Weisbecker
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