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Date:   Mon, 17 May 2021 13:27:49 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     syzbot <syzbot+0fb24f56fa707081e4f2@syzkaller.appspotmail.com>
Cc:     acme@kernel.org, alexander.shishkin@linux.intel.com,
        andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        daniel@iogearbox.net, john.fastabend@gmail.com, jolsa@redhat.com,
        kafai@fb.com, kpsingh@kernel.org, linux-kernel@vger.kernel.org,
        mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org,
        netdev@vger.kernel.org, songliubraving@fb.com,
        syzkaller-bugs@googlegroups.com, yhs@fb.com
Subject: Re: [syzbot] WARNING in __perf_install_in_context
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On Mon, May 17, 2021 at 03:56:22AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    18a3c5f7 Merge tag 'for_linus' of git://git.kernel.org/pub..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
> console output: https://syzkaller.appspot.com/x/log.txt?x=1662c153d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b8ac1fe5995f69d7
> dashboard link: https://syzkaller.appspot.com/bug?extid=0fb24f56fa707081e4f2
> userspace arch: riscv64
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+0fb24f56fa707081e4f2@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 8643 at kernel/events/core.c:2781 __perf_install_in_context+0x1c0/0x47c kernel/events/core.c:2781
> Modules linked in:
> CPU: 1 PID: 8643 Comm: syz-executor.0 Not tainted 5.12.0-rc8-syzkaller-00011-g18a3c5f7abfd #0
> Hardware name: riscv-virtio,qemu (DT)

How serious should I take this thing? ARM64 and x86_64 don't show these
errors.