Hello, syzbot found the following crash on: HEAD commit: 8f3d9f35 Linux 5.7-rc1 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=115720c3e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=5d351a1019ed81a2 dashboard link: https://syzkaller.appspot.com/bug?extid=66243bb7126c410cefe6 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+66243bb7126c410cefe6@xxxxxxxxxxxxxxxxxxxxxxxxx rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10500 ticks this GP) idle=57e/1/0x4000000000000002 softirq=44329/44329 fqs=5245 (t=10502 jiffies g=79401 q=2096) NMI backtrace for cpu 0 CPU: 0 PID: 23184 Comm: syz-executor.5 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x19b/0x1e5 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline] check_cpu_stall kernel/rcu/tree_stall.h:549 [inline] rcu_pending kernel/rcu/tree.c:3225 [inline] rcu_sched_clock_irq.cold+0x55d/0xcfa kernel/rcu/tree.c:2296 update_process_times+0x25/0x60 kernel/time/timer.c:1727 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x5ca/0xed0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline] smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 </IRQ> RIP: 0010:io_ring_ctx_wait_and_kill+0x98/0x5a0 fs/io_uring.c:7301 Code: 01 00 00 4d 89 f4 48 b8 00 00 00 00 00 fc ff df 4c 89 ed 49 c1 ec 03 48 c1 ed 03 49 01 c4 48 01 c5 eb 1c e8 3a ea 9d ff f3 90 <41> 80 3c 24 00 0f 85 53 04 00 00 48 83 bb 10 01 00 00 00 74 21 e8 RSP: 0018:ffffc9000897fdf0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff888024082080 RBX: ffff88808df8e000 RCX: 1ffff9200112ffab RDX: 0000000000000000 RSI: ffffffff81d549c6 RDI: ffff88808df8e300 RBP: ffffed1011bf1c2c R08: 0000000000000001 R09: ffffed1011bf1c61 R10: ffff88808df8e307 R11: ffffed1011bf1c60 R12: ffffed1011bf1c22 R13: ffff88808df8e160 R14: ffff88808df8e110 R15: ffffffff81d54ed0 io_uring_release+0x3e/0x50 fs/io_uring.c:7324 __fput+0x33e/0x880 fs/file_table.c:280 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x416421 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffc3c9f63d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416421 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 01ffffffffffffff R10: 0000000000770b20 R11: 0000000000000293 R12: 000000000076bfa0 R13: 0000000000770b30 R14: 0000000000000001 R15: 000000000076bfac --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
