linux-kernel - Re: [BUG] Stack overflow when running perf and function tracer

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Message-ID: <87v9ern82n.fsf@nanos.tec.linutronix.de>
Date:   Fri, 30 Oct 2020 14:42:56 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>, kan.liang@...ux.intel.com,
        like.xu@...ux.intel.com
Subject: Re: [BUG] Stack overflow when running perf and function tracer

On Fri, Oct 30 2020 at 12:36, Thomas Gleixner wrote:
> On Fri, Oct 30 2020 at 11:32, Peter Zijlstra wrote:
> So the real question is what else is on that stack which blows it up
> close to 4k? Btw, it would be massively helpful for this kind of crash
> to print the actual stack depth per entry in the backtrace.
>
> Here is the partial stack trace:
>                                                 Stack usage
>   ring_buffer_lock_reserve+0x12c/0x380          
>   trace_function+0x27/0x130
>   function_trace_call+0x133/0x180
>   perf_output_begin+0x4d/0x2d0                   64+
>   perf_log_throttle+0x9a/0x120                  470+
>   __perf_event_account_interrupt+0xa9/0x120
>   __perf_event_overflow+0x2b/0xf0               
>   __intel_pmu_pebs_event+0x2ec/0x3e0            760+
>   intel_pmu_drain_pebs_nhm+0x268/0x330          200+
>   handle_pmi_common+0xc2/0x2b0                  

So Steven provided a backtrace with the actual stack depth printed:

ring_buffer_lock_reserve+0x12c/0x380		0030  104
trace_function+0x27/0xf0			0098   56
function_trace_call+0x124/0x190			00d0  224 
__rcu_read_lock+0x5/0x20			01b0    8
perf_output_begin+0x4d/0x2d0			01b8  640
perf_log_throttle+0x9a/0x120			0438  624
__perf_event_account_interrupt+0xa6/0x120	06a8   32
__perf_event_overflow+0x2b/0xf0			06c8   48
__intel_pmu_pebs_event+0x2ec/0x3e0		06f8  960
intel_pmu_drain_pebs_nhm+0x268/0x330		0ab8  256
handle_pmi_common+0xc2/0x2b0			0bb8  584
intel_pmu_handle_irq+0xc8/0x160			0e00   64
perf_event_nmi_handler+0x28/0x50		0e40   32
nmi_handle+0x80/0x190				0e60   64
default_do_nmi+0x6b/0x170			0ea0   40
exc_nmi+0x15d/0x1a0				0ec8   40
end_repeat_nmi+0x16/0x55			0ef0  272

So I missed perf_output_begin and handle_pmi_common ...