INFO: task syz-executor.1:18937 blocked for more than 143 seconds. Not tainted 5.11.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:28464 pid:18937 ppid: 8442 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1854 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+0x163/0x260 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2838 nbd_start_device_ioctl drivers/block/nbd.c:1332 [inline] __nbd_ioctl drivers/block/nbd.c:1393 [inline] nbd_ioctl+0x5fd/0xa30 drivers/block/nbd.c:1433 blkdev_ioctl+0x29b/0x6c0 block/ioctl.c:576 block_ioctl+0xf9/0x140 fs/block_dev.c:1658 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465d99 RSP: 002b:00007f3ca8e38188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465d99 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00000000004bcf27 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe318418bf R14: 00007f3ca8e38300 R15: 0000000000022000 Showing all locks held in the system: 3 locks held by kworker/u4:5/203: 1 lock held by khungtaskd/1648: #0: ffffffff8bd73da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259 2 locks held by kworker/u5:0/2035: #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88801c39c138 ((wq_completion)knbd1-recv){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90007307da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 1 lock held by systemd-journal/4868: 1 lock held by in:imklog/8328: #0: ffff88802626e1b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 5 locks held by rs:main Q:Reg/8329: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1648 Comm: khungtaskd Not tainted 5.11.0-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+0x107/0x163 lib/dump_stack.c:120 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+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 203 Comm: kworker/u4:5 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:write_comp_data kernel/kcov.c:218 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x22/0x80 kernel/kcov.c:270 Code: 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 00 f0 01 00 48 89 ce 4c 8b 54 24 08 e8 de ef ff ff <84> c0 74 51 48 8b 81 b0 14 00 00 44 8b 81 ac 14 00 00 48 8b 10 49 RSP: 0018:ffffc90001167c10 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff888034f442e8 RCX: ffff88801270e080 RDX: 0000000000000000 RSI: ffff88801270e080 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff889cd4f6 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff88807249d6d0 R14: ffff88807249cbc0 R15: 000000000000005d FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe276932000 CR3: 0000000015367000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:649 [inline] batadv_nc_process_nc_paths.part.0+0x116/0x3b0 net/batman-adv/network-coding.c:683 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:675 [inline] batadv_nc_worker+0xaf2/0xe50 net/batman-adv/network-coding.c:724 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296