INFO: task syz-executor.2:14901 can't die for more than 143 seconds. syz-executor.2 D28040 14901 9329 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x72b/0xc60 kernel/time/timer.c:1871 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+0x29c/0x440 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2827 nbd_start_device_ioctl drivers/block/nbd.c:1301 [inline] __nbd_ioctl drivers/block/nbd.c:1376 [inline] nbd_ioctl+0xb2e/0xc44 drivers/block/nbd.c:1416 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x263/0x670 block/ioctl.c:717 block_ioctl+0xee/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:747 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a919 Code: Bad RIP value. RSP: 002b:00007f5080501c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045a919 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f50805026d4 R13: 00000000004c4646 R14: 00000000004d9e30 R15: 00000000ffffffff INFO: task syz-executor.2:14901 blocked for more than 143 seconds. Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28040 14901 9329 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x72b/0xc60 kernel/time/timer.c:1871 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+0x29c/0x440 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2827 nbd_start_device_ioctl drivers/block/nbd.c:1301 [inline] __nbd_ioctl drivers/block/nbd.c:1376 [inline] nbd_ioctl+0xb2e/0xc44 drivers/block/nbd.c:1416 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x263/0x670 block/ioctl.c:717 block_ioctl+0xee/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:747 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a919 Code: Bad RIP value. RSP: 002b:00007f5080501c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045a919 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f50805026d4 R13: 00000000004c4646 R14: 00000000004d9e30 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1110: #0: ffffffff899af980 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9196: #0: ffff88809e44b160 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:803 2 locks held by getty/9285: #0: ffff88808a158090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9286: #0: ffff8880a6815090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000170b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9287: #0: ffff8880a82a4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000177b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9288: #0: ffff88809f4f5090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000171b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9289: #0: ffff88809aa95090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000173b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9290: #0: ffff8880a87dc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000176b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9291: #0: ffff8882189f3090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900011342e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by knbd2-recv/14904: #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: __write_once_size include/linux/compiler.h:250 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:869 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a29f0928 ((wq_completion)knbd2-recv){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc90002247d30 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1110 Comm: khungtaskd Not tainted 5.5.0-rc2-next-20191220-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xdf1/0x14e0 kernel/hung_task.c:333 kthread+0x361/0x430 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 5.5.0-rc2-next-20191220-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_purge_orig RIP: 0010:lockdep_hardirqs_off+0xc8/0x2e0 kernel/locking/lockdep.c:3453 Code: 95 64 8b 48 ba 00 00 00 00 00 fc ff df 48 89 c1 83 e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 b9 01 00 00 <8b> 0d a2 3f 09 0a 85 c9 0f 84 ea 00 00 00 48 8d bb 68 08 00 00 48 RSP: 0018:ffffc90000cdfb68 EFLAGS: 00000097 RAX: 0000000000000003 RBX: ffff8880a99a81c0 RCX: 1ffffffff16c92ac RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffff8880a99a8a5c RBP: ffffc90000cdfb80 R08: ffff8880a99a81c0 R09: ffffed100ae5c587 R10: ffffed100ae5c586 R11: ffff8880572e2c33 R12: ffffffff81477bda R13: ffff8880a99a81c0 R14: ffffffff81477bda R15: 00000000000000ca FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe5b025eee CR3: 0000000097a44000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_hardirqs_off+0x62/0x240 kernel/trace/trace_preemptirq.c:45 __local_bh_enable_ip+0x11a/0x270 kernel/softirq.c:171 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_bh+0x2c/0x30 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:383 [inline] batadv_purge_orig_ref+0xc95/0x1370 net/batman-adv/originator.c:1366 batadv_purge_orig+0x1b/0x70 net/batman-adv/originator.c:1379 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352