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Date:   Sun, 11 Jul 2021 05:24:16 -0700
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Subject: [syzbot] INFO: task hung in io_uring_cancel_generic
From:   syzbot <syzbot+ba6fcd859210f4e9e109@syzkaller.appspotmail.com>
To:     asml.silence@gmail.com, axboe@kernel.dk, io-uring@vger.kernel.org,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    3dbdb38e Merge branch 'for-5.14' of git://git.kernel.org/p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14cd9efbd00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a1fcf15a09815757
dashboard link: https://syzkaller.appspot.com/bug?extid=ba6fcd859210f4e9e109
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13bbf280300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1111ec9c300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ba6fcd859210f4e9e109@syzkaller.appspotmail.com

INFO: task syz-executor015:8439 blocked for more than 143 seconds.
      Tainted: G        W         5.13.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor015 state:D stack:28184 pid: 8439 ppid:  8438 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0x934/0x2710 kernel/sched/core.c:5940
 schedule+0xd3/0x270 kernel/sched/core.c:6019
 io_uring_cancel_generic+0x54d/0x890 fs/io_uring.c:9203
 io_uring_files_cancel include/linux/io_uring.h:16 [inline]
 do_exit+0x28b/0x2a50 kernel/exit.c:780
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43eac9
RSP: 002b:00007ffc2d1b6378 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004b02f0 RCX: 000000000043eac9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00000000f0ffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004b02f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 1650 Comm: khungtaskd Tainted: G        W         5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd4b/0xfb0 kernel/hung_task.c:294
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:553


---
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