INFO: task syz-executor.2:19109 can't die for more than 143 seconds. syz-executor.2 D28648 19109 9649 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4152 schedule_timeout+0x570/0x860 kernel/time/timer.c:1874 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+0x26a/0x3c0 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x7ae/0xb7c drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x25b/0x660 block/ioctl.c:717 block_ioctl+0xe9/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: Bad RIP value. RSP: 002b:00007fa3b4ffcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa3b4ffd6d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003ff R14: 00000000004c69b5 R15: 000000000076bf0c INFO: task syz-executor.2:19109 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28648 19109 9649 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4152 schedule_timeout+0x570/0x860 kernel/time/timer.c:1874 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+0x26a/0x3c0 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x7ae/0xb7c drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x25b/0x660 block/ioctl.c:717 block_ioctl+0xe9/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: Bad RIP value. RSP: 002b:00007fa3b4ffcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa3b4ffd6d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003ff R14: 00000000004c69b5 R15: 000000000076bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1134: #0: ffffffff899adc80 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5544 1 lock held by rsyslogd/9508: #0: ffff888099a031a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/9598: #0: ffff8880a322d090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900019d32e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9599: #0: ffff8880a6017090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900019f32e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9600: #0: ffff88809f342090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900019832e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9601: #0: ffff8880a9652090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90001a132e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9602: #0: ffff8880a89fd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900019932e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9603: #0: ffff888095b9b090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90001a032e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9604: #0: ffff88808f40f090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900019532e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by kworker/u5:1/11779: #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: __write_once_size include/linux/compiler.h:250 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880988d1128 ((wq_completion)knbd2-recv){+.+.}, at: process_one_work+0x82a/0x1690 kernel/workqueue.c:2237 #1: ffffc9001733fdd0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x85e/0x1690 kernel/workqueue.c:2241 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1134 Comm: khungtaskd Not tainted 5.6.0-rc3-next-20200228-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:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xde3/0x14e0 kernel/hung_task.c:333 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 189 Comm: kworker/u4:5 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:747 [inline] RIP: 0010:trace_softirqs_off+0x1fa/0x360 kernel/locking/lockdep.c:3756 Code: c8 93 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 36 01 00 00 48 83 3d 6d 8f 3a 08 00 0f 84 1c 01 00 00 9c <58> 0f 1f 44 00 00 f6 c4 02 0f 84 cd fe ff ff e8 f2 e8 33 02 85 c0 RSP: 0018:ffffc90001757c20 EFLAGS: 00000086 RAX: 1ffffffff1327906 RBX: ffff8880a89642c0 RCX: 1ffffffff18c01e8 RDX: dffffc0000000000 RSI: 0000000000000201 RDI: 0000000000000000 RBP: ffffffff87a4e3ff R08: 0000000000000000 R09: 0000000000000001 R10: fffffbfff1852717 R11: ffffffff8c2938bf R12: ffff8880a89642c0 R13: ffffffff87a4ea60 R14: ffff8880597c0b80 R15: 000000000000003b FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00ebbf0b0 CR3: 000000009f554000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xdf/0x380 net/batman-adv/network-coding.c:441