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Date:   Tue, 25 Oct 2022 18:36:46 +0530
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Subject: Re: Perf: BUG: kernel NULL pointer dereference, address:
 0000000000000198
Content-Language: en-US
To:     Naresh Kamboju <naresh.kamboju@linaro.org>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        linux-perf-users@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>,
        regressions@lists.linux.dev, lkft-triage@lists.linaro.org
References: <CA+G9fYtOP-spGS7gYyBB-8wpUDiKxd5e_Nk05J9gzWR_DLBeFA@mail.gmail.com>
 <4429582f-155a-04d2-d139-a834bb325612@amd.com>
From:   Ravi Bangoria <ravi.bangoria@amd.com>
In-Reply-To: <4429582f-155a-04d2-d139-a834bb325612@amd.com>
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On 25-Oct-22 9:59 AM, Ravi Bangoria wrote:
> On 20-Oct-22 12:24 PM, Naresh Kamboju wrote:
>> Following kernel BUG noticed while running perf testing on qemu-x86-64.
> 
> Thanks Naresh. I'm aware of the crash[1] but haven't got a chance to
> root cause it. Let me try to spend some time on it.

I tried to mimic https://lkft.validation.linaro.org/scheduler/job/5708609.
However, I don't see a way to download lava-guest.qcow2. So I just used
rootfs and kernel:

  /usr/bin/qemu-system-x86_64 -cpu host -enable-kvm -nographic -net nic,model=virtio,macaddr=DE:AD:BE:EF:66:20 -net user -m 1024 -monitor none -kernel bzImage --append "root=/dev/sda  rootwait console=ttyS0,115200" -hda lkft-console-image-intel-corei7-64-20221019172733.rootfs.ext4 -m 4096 -smp 4 -nographic

And I ran perf test inside the guest, which ran fine.

Would it be possible for you to redo the experiment and see if you are able
to reproduce it consistently.

Thanks,
Ravi