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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Mon, 17 May 2021 17:42:41 +0200
Message-ID: <CACT4Y+b2CzUxXyNJti=+7vbmQQg6=Ryjxp6orfrqvD8dmkhfGw@mail.gmail.com>
Subject: Re: [syzbot] WARNING in task_ctx_sched_out
To:     syzbot <syzbot+30189c98403be62bc05a@syzkaller.appspotmail.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv <linux-riscv@lists.infradead.org>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Jiri Olsa <jolsa@redhat.com>, Martin KaFai Lau <kafai@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        netdev <netdev@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Song Liu <songliubraving@fb.com>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Yonghong Song <yhs@fb.com>
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On Mon, May 17, 2021 at 5:10 PM syzbot
<syzbot+30189c98403be62bc05a@syzkaller.appspotmail.com> 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=1569c027d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b8ac1fe5995f69d7
> dashboard link: https://syzkaller.appspot.com/bug?extid=30189c98403be62bc05a
> 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+30189c98403be62bc05a@syzkaller.appspotmail.com

Another perf warning on riscv64:

WARNING in __perf_install_in_context
https://syzkaller.appspot.com/bug?id=ca4bae83abaaa2be86e4dc7925343fae9abb6056
https://groups.google.com/g/syzkaller-bugs/c/sc87fhg7Vhg/m/7_cuuqu9BAAJ


> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 8711 at kernel/events/core.c:2668 task_ctx_sched_out+0x5c/0x60 kernel/events/core.c:2668
> Modules linked in:
> CPU: 0 PID: 8711 Comm: syz-executor.0 Not tainted 5.12.0-rc8-syzkaller-00011-g18a3c5f7abfd #0
> Hardware name: riscv-virtio,qemu (DT)
> epc : task_ctx_sched_out+0x5c/0x60 kernel/events/core.c:2668
>  ra : task_ctx_sched_out+0x5c/0x60 kernel/events/core.c:2668
> epc : ffffffe00027ccf0 ra : ffffffe00027ccf0 sp : ffffffe0067abb80
>  gp : ffffffe0045883c0 tp : ffffffe00db797c0 t0 : ffffffc400b23834
>  t1 : 0000000000000001 t2 : 00000000000f4240 s0 : ffffffe0067abbb0
>  s1 : ffffffe066d59e00 a0 : ffffffe066d59fa8 a1 : 00000000000f0000
>  a2 : 0000000000000002 a3 : ffffffe00027ccf0 a4 : ffffffe00db7a7c0
>  a5 : 0000000000000000 a6 : 0000000000f00000 a7 : ffffffe00028fc4c
>  s2 : ffffffe00877e400 s3 : 0000000000000003 s4 : ffffffe00df38800
>  s5 : ffffffe00db7ab48 s6 : ffffffe00db7aab8 s7 : ffffffe00877e408
>  s8 : 0000000000000000 s9 : 0000000000000025 s10: ffffffe00db797c0
>  s11: ffffffe0067abe30 t3 : 1ef9635ec2383300 t4 : ffffffc404c957b2
>  t5 : ffffffc404c957ba t6 : 0000000000040000
> status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003
> Call Trace:
> [<ffffffe00027ccf0>] task_ctx_sched_out+0x5c/0x60 kernel/events/core.c:2668
> [<ffffffe00028fc98>] perf_event_exit_task_context kernel/events/core.c:12483 [inline]
> [<ffffffe00028fc98>] perf_event_exit_task+0x214/0x708 kernel/events/core.c:12541
> [<ffffffe000031fc4>] do_exit+0x77a/0x1846 kernel/exit.c:834
> [<ffffffe00003319a>] do_group_exit+0xa0/0x198 kernel/exit.c:922
> [<ffffffe00004c558>] get_signal+0x31e/0x14ba kernel/signal.c:2781
> [<ffffffe000007e06>] do_signal arch/riscv/kernel/signal.c:271 [inline]
> [<ffffffe000007e06>] do_notify_resume+0xa8/0x930 arch/riscv/kernel/signal.c:317
> [<ffffffe000005586>] ret_from_exception+0x0/0x14
> irq event stamp: 3704
> hardirqs last  enabled at (3703): [<ffffffe002a9a784>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
> hardirqs last  enabled at (3703): [<ffffffe002a9a784>] _raw_spin_unlock_irqrestore+0x68/0x98 kernel/locking/spinlock.c:191
> hardirqs last disabled at (3704): [<ffffffe002a9a41c>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:126 [inline]
> hardirqs last disabled at (3704): [<ffffffe002a9a41c>] _raw_spin_lock_irq+0x5c/0x5e kernel/locking/spinlock.c:167
> softirqs last  enabled at (3672): [<ffffffe002a9b578>] __do_softirq+0x5e0/0x8c4 kernel/softirq.c:372
> softirqs last disabled at (3667): [<ffffffe00003507e>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
> softirqs last disabled at (3667): [<ffffffe00003507e>] invoke_softirq kernel/softirq.c:228 [inline]
> softirqs last disabled at (3667): [<ffffffe00003507e>] __irq_exit_rcu kernel/softirq.c:422 [inline]
> softirqs last disabled at (3667): [<ffffffe00003507e>] irq_exit+0x1a0/0x1b6 kernel/softirq.c:446
> ---[ end trace 2de0fbf815e6ece8 ]---
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
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>
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