INFO: task syz-executor.5:8531 blocked for more than 143 seconds. Not tainted 5.4.0-rc1+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28000 8531 8195 0x00004004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x74b/0xb80 kernel/sched/core.c:4069 schedule+0x131/0x1e0 kernel/sched/core.c:4136 schedule_timeout+0x46/0x240 kernel/time/timer.c:1871 do_wait_for_common+0x2e7/0x4d0 kernel/sched/completion.c:83 __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x47/0x60 kernel/sched/completion.c:136 flush_workqueue+0x60d/0x14b0 kernel/workqueue.c:2826 nbd_start_device_ioctl drivers/block/nbd.c:1272 [inline] __nbd_ioctl drivers/block/nbd.c:1347 [inline] nbd_ioctl+0x9d2/0xac0 drivers/block/nbd.c:1387 __blkdev_driver_ioctl block/ioctl.c:304 [inline] blkdev_ioctl+0x807/0x2980 block/ioctl.c:606 block_ioctl+0xbd/0x100 fs/block_dev.c:1954 do_vfs_ioctl+0x744/0x1730 fs/ioctl.c:46 ksys_ioctl fs/ioctl.c:713 [inline] __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0xe3/0x120 fs/ioctl.c:718 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a59 Code: Bad RIP value. RSP: 002b:00007f3d161d2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000459a59 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3d161d36d4 R13: 00000000004c33a9 R14: 00000000004d6fc0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1064: #0: ffffffff888d3ec0 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 2 locks held by kworker/u5:0/1523: #0: ffff88809e177e28 ((wq_completion)knbd5-recv){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff88809e177e28 ((wq_completion)knbd5-recv){+.+.}, at: process_one_work+0x75d/0x10e0 kernel/workqueue.c:2242 #1: ffff8880a5c8fd78 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x79f/0x10e0 kernel/workqueue.c:2244 2 locks held by rsyslogd/8057: #0: ffff88808f480d60 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x243/0x2e0 fs/file.c:801 #1: ffff8880aea34998 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1215 [inline] #1: ffff8880aea34998 (&rq->lock){-.-.}, at: __schedule+0xd6/0xb80 kernel/sched/core.c:4017 2 locks held by getty/8147: #0: ffff8880a75a2d10 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f052e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8148: #0: ffff888087560250 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f0d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8149: #0: ffff888096dcf390 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f112e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8150: #0: ffff8880954f29d0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005ee92e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8151: #0: ffff888099377410 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8152: #0: ffff888094cbaa50 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005efd2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8153: #0: ffff888087a94590 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005ee12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1064 Comm: khungtaskd Not tainted 5.4.0-rc1+ #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+0x1d8/0x2f8 lib/dump_stack.c:113 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xbb9/0xbd0 kernel/hung_task.c:289 kthread+0x332/0x350 kernel/kthread.c:255 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: 7 Comm: kworker/u4:0 Not tainted 5.4.0-rc1+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_release kernel/locking/lockdep.c:4271 [inline] RIP: 0010:lock_release+0x233/0x780 kernel/locking/lockdep.c:4506 Code: e7 ff ff 0f 00 41 09 c7 8a 04 13 84 c0 0f 85 45 04 00 00 44 89 3e 41 f7 c5 ff 0f 00 00 0f 85 51 02 00 00 48 8b 45 98 8a 04 10 <84> c0 0f 85 53 04 00 00 48 8b 45 c0 44 89 20 4c 89 f0 48 c1 e8 03 RSP: 0018:ffff8880a9887bd8 EFLAGS: 00000046 RAX: 1ffff1101530d900 RBX: 1ffff1101530d959 RCX: ffffffff81589437 RDX: dffffc0000000000 RSI: ffff8880a986cac8 RDI: ffff8880a986caa8 RBP: ffff8880a9887c58 R08: dffffc0000000000 R09: fffffbfff117c795 R10: fffffbfff117c795 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffff8880a986caa8 R15: 0000000000020029 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000008b460000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release+0x26/0x30 include/linux/rcupdate.h:213 rcu_read_unlock include/linux/rcupdate.h:653 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:411 [inline] batadv_nc_worker+0x281/0x600 net/batman-adv/network-coding.c:718 process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352