From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [perf] crashing bug in icl_update_topdown_event
Date: Thu, 12 Jun 2025 10:47:30 -0400 [thread overview]
Message-ID: <36b65ee5-4bce-4b15-91bc-52604bc8a046@linux.intel.com> (raw)
In-Reply-To: <704f6604-547b-f7ca-ad45-2afd2dd70456@maine.edu>
On 2025-06-11 3:28 p.m., Vince Weaver wrote:
> On Wed, 11 Jun 2025, Liang, Kan wrote:
>
>>
>>
>> It seems an regression from the f9bdf1f95339 ("perf/x86/intel: Avoid
>> disable PMU if !cpuc->enabled in sample read").
>> The commit merged the intel_pmu_auto_reload_read() and
>> intel_pmu_read_topdown_event(). It's possible that a PEBS event 0x0400
>> runs on a ATOM CPU. So the PERF_X86_EVENT_AUTO_RELOAD is set for the
>> event. The is_topdown_event() also returns true.
>>
>> Does the below patch help?
>> It checks the PERF_X86_EVENT_TOPDOWN flag as well before invoking the
>> topdown functions.
>
> With this patch applied my test case no longer crashes.
>
Thanks for the test. I've posted a fix to LKML.
https://lore.kernel.org/linux-perf-users/20250612143818.2889040-1-kan.liang@linux.intel.com/
It's a little bit different from the one tested. Please check and
provide a 'tested-by' on the new patch if it works.Thanks,Kan
next prev parent reply other threads:[~2025-06-12 14:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-11 14:45 [perf] crashing bug in icl_update_topdown_event Vince Weaver
2025-06-11 14:57 ` Vince Weaver
2025-06-11 18:53 ` Liang, Kan
2025-06-11 19:28 ` Vince Weaver
2025-06-12 14:47 ` Liang, Kan [this message]
2025-06-12 16:08 ` Vince Weaver
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