From: Sandipan Das <sandipan.das@amd.com>
To: Peter Zijlstra <peterz@infradead.org>,
Mario Limonciello <mario.limonciello@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-pm@vger.kernel.org, rafael@kernel.org, pavel@ucw.cz,
linux-perf-users@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH 2/2] perf/x86/amd: Don't allow pre-emption in amd_pmu_lbr_reset()
Date: Wed, 25 Oct 2023 17:17:34 +0530 [thread overview]
Message-ID: <fe834675-a745-42ba-ae4a-97f003f84d10@amd.com> (raw)
In-Reply-To: <20231024163450.GB13938@noisy.programming.kicks-ass.net>
On 10/24/2023 10:04 PM, Peter Zijlstra wrote:
> On Tue, Oct 24, 2023 at 06:30:38PM +0200, Peter Zijlstra wrote:
>> On Tue, Oct 24, 2023 at 11:04:06AM -0500, Mario Limonciello wrote:
>>
>>>> IIRC this is the hotplug thread running a teardown function on that CPU
>>>> itself. It being a strict per-cpu thread should not trip
>>>> smp_processor_id() wanrs.
>>>>
>>>
>>> BUG: using smp_processor_id() in preemptible [00000000] code: rtcwake/2960
>>> caller is amd_pmu_lbr_reset+0x19/0xc0
>>> CPU: 104 PID: 2960 Comm: rtcwake Not tainted 6.6.0-rc6-00002-g3e2c7f3ac51f
>>
>> Very much not the cpuhp/%u thread :/, let me try and figure out how that
>> happens.
>
> Uhh, my bad, these are the PREPARE/DEAD handlers, they run before online
> and after dying. The CPU is completely dead. Running lbr_reset() here
> makes no sense.
>
> Did that want to be in amd_pmu_cpu_dying() ?
>
Agreed, it should have gone into the cpu_dying() callback. lbr_reset() is called
once from cpu_starting() so I wonder if its necessary to call it again in the
CPU offline path.
next prev parent reply other threads:[~2023-10-25 11:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-23 16:00 [PATCH 0/2] Fixes for s3 with parallel bootup Mario Limonciello
2023-10-23 16:00 ` [PATCH 1/2] x86: Enable x2apic during resume from suspend if used previously Mario Limonciello
2023-10-24 8:36 ` Ingo Molnar
2023-10-24 15:36 ` Mario Limonciello
2023-10-24 17:01 ` Ingo Molnar
2023-10-25 19:04 ` Mario Limonciello
2023-10-24 17:30 ` Tom Lendacky
2023-10-23 16:00 ` [PATCH 2/2] perf/x86/amd: Don't allow pre-emption in amd_pmu_lbr_reset() Mario Limonciello
2023-10-24 8:02 ` Ingo Molnar
2023-10-24 15:32 ` Mario Limonciello
2023-10-24 15:59 ` Peter Zijlstra
2023-10-24 16:04 ` Mario Limonciello
2023-10-24 16:30 ` Peter Zijlstra
2023-10-24 16:34 ` Peter Zijlstra
2023-10-25 11:47 ` Sandipan Das [this message]
2023-10-24 16:51 ` Ingo Molnar
2023-10-24 18:30 ` Mario Limonciello
2023-10-24 22:24 ` Peter Zijlstra
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