INFO: task syz-executor.2:10725 blocked for more than 143 seconds. Not tainted 5.7.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28400 10725 7229 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874 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+0x16a/0x270 kernel/sched/completion.c:138 flush_workqueue+0x403/0x14f0 kernel/workqueue.c:2831 nbd_start_device_ioctl drivers/block/nbd.c:1322 [inline] __nbd_ioctl drivers/block/nbd.c:1397 [inline] nbd_ioctl+0x7ae/0xb7f drivers/block/nbd.c:1437 __blkdev_driver_ioctl block/ioctl.c:322 [inline] blkdev_ioctl+0x25b/0x660 block/ioctl.c:718 block_ioctl+0xf9/0x140 fs/block_dev.c:2005 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:771 __do_sys_ioctl fs/ioctl.c:780 [inline] __se_sys_ioctl fs/ioctl.c:778 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: Bad RIP value. RSP: 002b:00007f18e8f9dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e8e20 RCX: 000000000045c829 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000409 R14: 00000000004c6a64 R15: 00007f18e8f9e6d4 Showing all locks held in the system: 1 lock held by khungtaskd/1144: #0: ffffffff899beb00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/6951: #0: ffff88809e9c8db0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by kworker/u4:9/8394: #0: ffff8880ae637998 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x9be/0xdb0 kernel/sched/fair.c:10512 #1: ffffffff899beb00 (rcu_read_lock){....}-{1:2}, at: __update_idle_core+0x42/0x3e0 kernel/sched/fair.c:5969 2 locks held by kworker/u5:1/8524: #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a8d41138 ((wq_completion)knbd2-recv){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239 #1: ffffc90017037dc0 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1144 Comm: khungtaskd Not tainted 5.7.0-rc4-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+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_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8394 Comm: kworker/u4:9 Not tainted 5.7.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:trace_lock_release include/trace/events/lock.h:58 [inline] RIP: 0010:lock_release+0x592/0x800 kernel/locking/lockdep.c:4951 Code: 0f 85 f2 fb ff ff e8 41 f8 a6 ff e9 e8 fb ff ff 4c 89 ea 4c 89 e6 48 89 ef e8 0a 60 ff ff e9 5a fe ff ff 65 ff 05 66 a0 a8 7e <48> 8b 05 ff 56 2b 09 e8 72 30 06 00 85 c0 74 0d 80 3d 12 f6 2a 09 RSP: 0018:ffffc90016cb7c00 EFLAGS: 00000083 RAX: 0000000000000001 RBX: 1ffff92002d96f83 RCX: ffffffff81597a5b RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8a895480 RBP: 0000000000000000 R08: ffff88808ed302c0 R09: fffffbfff1512a91 R10: ffffffff8a895487 R11: fffffbfff1512a90 R12: ffffffff899beb00 R13: ffffffff87b616d6 R14: dffffc0000000000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac4feb0000 CR3: 00000000a6563000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:213 [inline] rcu_read_unlock include/linux/rcupdate.h:655 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:411 [inline] batadv_nc_worker+0x21c/0x760 net/batman-adv/network-coding.c:718 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352