INFO: task syz-executor.5:4542 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28560 4542 8115 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2713 nbd_start_device_ioctl drivers/block/nbd.c:1276 [inline] __nbd_ioctl drivers/block/nbd.c:1347 [inline] nbd_ioctl+0x75b/0xbe0 drivers/block/nbd.c:1387 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x5cb/0x1a80 block/ioctl.c:601 block_ioctl+0xe9/0x130 fs/block_dev.c:1906 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3fbb828639 Code: Bad RIP value. RSP: 002b:00007f3fb9d9b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3fbb948f80 RCX: 00007f3fbb828639 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f3fbb8837e1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffed7dffbf R14: 00007f3fb9d9b300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1568: #0: 0000000029e09016 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by in:imklog/7781: #0: 0000000097f49c3a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 1 lock held by syz-executor.0/8124: 2 locks held by kworker/u5:0/18417: #0: 000000006f5afc82 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000006d586378 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 1 lock held by syz-executor.2/12656: #0: 0000000085f4f233 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9702 [inline] #0: 0000000085f4f233 (&rq->lock){-.-.}, at: pick_next_task_fair+0x556/0x1570 kernel/sched/fair.c:6841 1 lock held by syz-executor.0/12652: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1568 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9358 Comm: kworker/u4:6 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: bat_events batadv_nc_worker RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:314 [inline] RIP: 0010:__lock_acquire+0x880/0x3ff0 kernel/locking/lockdep.c:3411 Code: 24 31 c8 89 c1 29 c2 44 01 c0 c1 c1 08 31 ca 89 d1 41 29 d0 01 c2 c1 c1 10 89 d6 41 31 c8 44 89 c1 44 29 c0 41 01 d0 c1 c9 0d <31> c8 89 c1 29 c6 44 01 c0 c1 c1 04 31 f1 48 c1 e1 20 48 09 c1 48 RSP: 0018:ffff88804c427a68 EFLAGS: 00000083 RAX: 00000000a4b8343c RBX: 9cfb8927f9a08238 RCX: 00000000fd9013db RDX: 000000008f360d1b RSI: 000000008f360d1b RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000091b18ccd R09: 0000000000000002 R10: ffff8880a915ecd8 R11: 0000000000000000 R12: 000000000002002e R13: ffff8880a915e400 R14: ffff8880a915ecf0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055dc3140aa60 CR3: 000000009bc1c000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0x12d/0xd50 net/batman-adv/network-coding.c:730 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415