block nbd2: shutting down sockets block nbd3: shutting down sockets block nbd0: Device being setup by another task block nbd0: shutting down sockets block nbd1: shutting down sockets INFO: task syz-executor.4:7906 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D27752 7906 6606 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: Bad RIP value. RSP: 002b:00007f3194f46c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3194f476d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c INFO: task syz-executor.5:7903 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28136 7903 6609 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: Bad RIP value. RSP: 002b:00007f4a45a61c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4a45a626d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c INFO: task syz-executor.3:7907 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28136 7907 6592 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: Bad RIP value. RSP: 002b:00007f3d383d1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3d383d26d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c INFO: task syz-executor.2:7904 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D26728 7904 6590 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: Bad RIP value. RSP: 002b:00007fee69c5ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fee69c5f6d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c INFO: task syz-executor.0:7929 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D27512 7929 6594 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: 48 83 ec 10 48 89 6c 24 08 48 8d 6c 24 08 48 8b 42 08 48 8b 40 08 48 89 04 24 e8 62 a3 fc ff 48 8b 6c 24 08 48 83 c4 10 c3 e8 36 00 00 eb c1 cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 72 RSP: 002b:00007fc5157d8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc5157d96d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c INFO: task syz-executor.1:7951 blocked for more than 140 seconds. Not tainted 4.19.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27800 7951 6611 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6e1/0xe00 kernel/time/timer.c:1801 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x282/0x460 kernel/sched/completion.c:136 flush_workqueue+0x35d/0x13c0 kernel/workqueue.c:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x2c8/0xb20 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7fc/0x17a0 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c749 Code: 48 83 ec 10 48 89 6c 24 08 48 8d 6c 24 08 48 8b 42 08 48 8b 40 08 48 89 04 24 e8 62 a3 fc ff 48 8b 6c 24 08 48 83 c4 10 c3 e8 36 00 00 eb c1 cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 72 RSP: 002b:00007f3085a9dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3085a9e6d4 RCX: 000000000045c749 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fb R14: 00000000004c6889 R15: 000000000076bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1082: #0: 0000000078635dc7 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 2 locks held by kworker/u5:0/1218: #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000003ca07661 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 0000000098b70284 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 1 lock held by in:imklog/6085: 2 locks held by kworker/u5:1/7912: #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000efac1b40 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 000000004f30fbcd ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 2 locks held by kworker/u5:2/7918: #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000de3be564 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 00000000b1d6e236 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 2 locks held by kworker/u5:3/7919: #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000cf71b081 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 00000000096de327 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 2 locks held by kworker/u5:4/7921: #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000008b420114 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 00000000082678ee ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 2 locks held by kworker/u5:5/7931: #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000d768b686 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 000000004eff94ec ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1082 Comm: khungtaskd Not tainted 4.19.142-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x177 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.4+0x3e/0x76 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xe6/0x11a lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6091 Comm: rs:main Q:Reg Not tainted 4.19.142-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0033:0x564fe013b308 Code: 00 41 8b 34 24 8d 86 60 f0 ff ff 83 f8 0b 0f 86 2b fc ff ff 48 8d 3d 8f 4e 03 00 31 c0 e8 e0 c6 fe ff e9 eb fc ff ff 0f 1f 00 <41> 0f b7 56 46 0f a3 d0 0f 83 95 fd ff ff 8b 0b 85 c9 0f 85 82 06 RSP: 002b:00007fa62a512ac0 EFLAGS: 00000286 RAX: 00000000000000ff RBX: 0000564fe039bbec RCX: 0000000000000001 RDX: 0000564fe01703a8 RSI: 0000000000000fa1 RDI: 0000000000000000 RBP: 0000564fe0a81220 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000564fe0a87880 R13: 0000564fe039bbec R14: 00007fa624002080 R15: 0000564fe0a81250 FS: 00007fa62a513700 GS: 0000000000000000