Subject: [syzbot] WARNING in task_ctx_sched_out

From: syzbot <[email-masked]>
Date: Mon, 17 May 2021 08:10:19 -0700

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: [email-masked]

------------[ 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 ]---

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