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Subject: Re: [PATCH] perf jevents: Fix segfault in perf_pmu__find_events_table
To:     Namhyung Kim <namhyung@kernel.org>
CC:     <peterz@infradead.org>, <mingo@redhat.com>, <acme@kernel.org>,
        <mark.rutland@arm.com>, <alexander.shishkin@linux.intel.com>,
        <jolsa@kernel.org>, <irogers@google.com>,
        <adrian.hunter@intel.com>, <linux-perf-users@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20230918030304.24832-1-yangjihong1@huawei.com>
 <CAM9d7cjCwykJ+9oB_u1cP+qgLNbwUCFhR31iK9rfjfSFxs13fg@mail.gmail.com>
From:   Yang Jihong <yangjihong1@huawei.com>
Message-ID: <10d67fbc-49b2-25ff-6d02-e13d6a22bced@huawei.com>
Date:   Tue, 19 Sep 2023 09:50:09 +0800
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Hello,

On 2023/9/19 7:55, Namhyung Kim wrote:
> Hello,
> 
> On Sun, Sep 17, 2023 at 8:05 PM Yang Jihong <yangjihong1@huawei.com> wrote:
>>
>> Before caching the JSON events table, perf_pmu__find_events_table() need
>> to check whether table is empty.
>>
>> For example, AuthenticAMD-15-6B-1 is used. The matching events table cannot
>> be found. As a result, a null pointer is accessed when caching JSON events
>> table, causing segfault.
>>
>> Before:
>>    # perf record -vv true
>>    DEBUGINFOD_URLS=
>>    Using CPUID AuthenticAMD-15-6B-1
>>    Segmentation fault (core dumped)
>>
>> After:
>>    # perf record -vv true
>>    DEBUGINFOD_URLS=
>>    Using CPUID AuthenticAMD-15-6B-1
>>    <SNIP>
>>    [ perf record: Woken up 1 times to write data ]
>>    [ perf record: Captured and wrote 0.005 MB perf.data ]
>>
>> Fixes: 7c52f10c0d4d ("perf pmu: Cache JSON events table")
>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
> 
> Thanks for the fix but please see
> 
> https://lore.kernel.org/all/20230913125157.2790375-1-tmricht@linux.ibm.com/
> 

Uh.. no notice that there is already a fix, please ignore it.

Thanks,
Yang