From: Ravi Bangoria <ravi.bangoria@amd.com>
To: George Kennedy <george.kennedy@oracle.com>
Cc: harshit.m.mogalapalli@oracle.com, peterz@infradead.org,
mingo@redhat.com, acme@kernel.org, namhyung@kernel.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com,
kan.liang@linux.intel.com, tglx@linutronix.de, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
ravi.bangoria@amd.com
Subject: Re: [PATCH] perf/x86/amd: check event before enable to avoid GPF
Date: Thu, 30 May 2024 09:07:30 +0530 [thread overview]
Message-ID: <75f6aba1-8ed6-4ef8-8811-de40ae40be90@amd.com> (raw)
In-Reply-To: <1716990659-2427-1-git-send-email-george.kennedy@oracle.com>
Hi George,
> Events can be deleted and the entry can be NULL.
Can you please also explain "how".
> Check event for NULL in amd_pmu_enable_all() before enable to avoid a GPF.
> This appears to be an AMD only issue.
>
> Syzkaller reported a GPF in amd_pmu_enable_all.
Can you please provide a bug report link? Also, any reproducer?
> @@ -760,7 +760,8 @@ static void amd_pmu_enable_all(int added)
> if (!test_bit(idx, cpuc->active_mask))
> continue;
>
> - amd_pmu_enable_event(cpuc->events[idx]);
> + if (cpuc->events[idx])
> + amd_pmu_enable_event(cpuc->events[idx]);
What if cpuc->events[idx] becomes NULL after if (cpuc->events[idx]) but
before amd_pmu_enable_event(cpuc->events[idx])?
Thanks,
Ravi
next prev parent reply other threads:[~2024-05-30 3:37 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-29 13:50 George Kennedy
2024-05-30 3:37 ` Ravi Bangoria [this message]
2024-05-30 18:30 ` George Kennedy
2024-05-30 20:26 ` George Kennedy
2024-06-04 13:16 ` Ravi Bangoria
2024-06-04 13:23 ` George Kennedy
2024-06-04 13:40 ` Ravi Bangoria
2024-06-04 14:26 ` George Kennedy
2024-06-07 19:13 ` George Kennedy
2024-06-10 10:51 ` Ravi Bangoria
2024-06-24 16:18 ` George Kennedy
2024-07-01 14:15 ` George Kennedy
2024-07-02 4:03 ` Ravi Bangoria
2024-07-02 11:38 ` George Kennedy
2024-09-24 17:13 ` George Kennedy
2024-09-26 4:05 ` Ravi Bangoria
2024-06-03 4:39 ` Ravi Bangoria
2024-06-03 13:30 ` George Kennedy
2024-06-04 13:02 ` Ravi Bangoria
2024-06-04 13:00 ` Ravi Bangoria
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