INFO: task syz-executor366:6549 can't die for more than 143 seconds. task:syz-executor366 state:D stack:27528 pid: 6549 ppid: 6548 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4955 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6302 schedule+0xd3/0x270 kernel/sched/core.c:6381 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x176/0x280 kernel/sched/completion.c:138 flush_workqueue+0x3ed/0x15b0 kernel/workqueue.c:2869 nbd_start_device_ioctl drivers/block/nbd.c:1359 [inline] __nbd_ioctl drivers/block/nbd.c:1422 [inline] nbd_ioctl+0x631/0xa80 drivers/block/nbd.c:1462 blkdev_ioctl+0x2a1/0x700 block/ioctl.c:589 block_ioctl+0xf9/0x140 fs/block_dev.c:1421 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 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: 0033:0x4441e9 RSP: 002b:00007ffcc7ad2b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004004a0 RCX: 00000000004441e9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffcc7ad2cd8 R09: 00007ffcc7ad2cd8 R10: 00007ffcc7ad2cd8 R11: 0000000000000246 R12: 0000000000403500 R13: 431bde82d7b634db R14: 00000000004b2018 R15: 00000000004004a0 INFO: task syz-executor366:6549 blocked for more than 143 seconds. Not tainted 5.14.0-next-20210831-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor366 state:D stack:27528 pid: 6549 ppid: 6548 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4955 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6302 schedule+0xd3/0x270 kernel/sched/core.c:6381 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x176/0x280 kernel/sched/completion.c:138 flush_workqueue+0x3ed/0x15b0 kernel/workqueue.c:2869 nbd_start_device_ioctl drivers/block/nbd.c:1359 [inline] __nbd_ioctl drivers/block/nbd.c:1422 [inline] nbd_ioctl+0x631/0xa80 drivers/block/nbd.c:1462 blkdev_ioctl+0x2a1/0x700 block/ioctl.c:589 block_ioctl+0xf9/0x140 fs/block_dev.c:1421 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 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: 0033:0x4441e9 RSP: 002b:00007ffcc7ad2b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004004a0 RCX: 00000000004441e9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffcc7ad2cd8 R09: 00007ffcc7ad2cd8 R10: 00007ffcc7ad2cd8 R11: 0000000000000246 R12: 0000000000403500 R13: 431bde82d7b634db R14: 00000000004b2018 R15: 00000000004004a0 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8b97fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 2 locks held by kworker/u5:0/151: #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff88801e1f3138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2268 #1: ffffc9000138fdb0 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2272 1 lock held by in:imklog/6257: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.14.0-next-20210831-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 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 CPU: 1 PID: 2964 Comm: systemd-journal Not tainted 5.14.0-next-20210831-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lock_release+0xc/0x720 kernel/locking/lockdep.c:5633 Code: e9 55 fe ff ff 48 c7 c7 e8 9b 6e 8d e8 8d d2 60 00 e9 6d fd ff ff 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 41 57 <41> 56 41 55 41 54 49 89 fc 55 53 48 81 ec 90 00 00 00 48 8d 6c 24 RSP: 0018:ffffc90002b2fee8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff88807bfb3900 RCX: 1ffff1100f7f6800 RDX: ffffffff893255af RSI: ffffffff893255af RDI: ffff88807bfb3fc0 RBP: ffff88807bfb3fb8 R08: 0000000000000001 R09: ffffffff8eef904f R10: ffffffff8eef9057 R11: 0000000000000001 R12: ffff88807bfb3fc0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f45705b98c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f456d98e000 CR3: 0000000019eaa000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_write_seqcount_end include/linux/seqlock.h:565 [inline] vtime_user_enter+0xea/0x170 kernel/sched/cputime.c:712 __context_tracking_enter+0xef/0x100 kernel/context_tracking.c:82 user_enter_irqoff include/linux/context_tracking.h:41 [inline] __exit_to_user_mode kernel/entry/common.c:130 [inline] syscall_exit_to_user_mode+0x48/0x60 kernel/entry/common.c:304 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f456f851f17 Code: ff ff ff 48 8b 4d a0 0f b7 51 fe 48 8b 4d a8 66 89 54 08 fe e9 1a ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007fff41f8d4b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000027 RAX: 0000000000000b94 RBX: 0000564c33bff1e0 RCX: 00007f456f851f17 RDX: 00007fff41f8d578 RSI: 0000000000000001 RDI: 0000564c33bff1e0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000206 R12: 00007fff41f8d578 R13: 0000000000000b94 R14: 00007fff41f90360 R15: 00007fff41f8d970 ---------------- Code disassembly (best guess): 0: e9 55 fe ff ff jmpq 0xfffffe5a 5: 48 c7 c7 e8 9b 6e 8d mov $0xffffffff8d6e9be8,%rdi c: e8 8d d2 60 00 callq 0x60d29e 11: e9 6d fd ff ff jmpq 0xfffffd83 16: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 1d: 00 1e: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 25: fc ff df 28: 41 57 push %r15 * 2a: 41 56 push %r14 <-- trapping instruction 2c: 41 55 push %r13 2e: 41 54 push %r12 30: 49 89 fc mov %rdi,%r12 33: 55 push %rbp 34: 53 push %rbx 35: 48 81 ec 90 00 00 00 sub $0x90,%rsp 3c: 48 rex.W 3d: 8d .byte 0x8d 3e: 6c insb (%dx),%es:(%rdi) 3f: 24 .byte 0x24