BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 149s! INFO: task syz-executor5:15693 blocked for more than 140 seconds. Not tainted 4.14.71+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D28424 15693 1845 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x3bc/0x4e0 kernel/sched/completion.c:123 flush_work+0x3b8/0x6e0 kernel/workqueue.c:2885 flush_all_backlogs net/core/dev.c:4638 [inline] rollback_registered_many+0x505/0xac0 net/core/dev.c:7168 rollback_registered+0xe0/0x1a0 net/core/dev.c:7224 unregister_netdevice_queue+0x1a1/0x220 net/core/dev.c:8212 unregister_netdevice include/linux/netdevice.h:2427 [inline] ppp_release+0x175/0x1a0 drivers/net/ppp/ppp_generic.c:408 __fput+0x25e/0x6f0 fs/file_table.c:210 task_work_run+0x116/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x12e/0x150 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:267 [inline] do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x411151 RSP: 002b:00007ffdef539270 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411151 RDX: 0000000000000001 RSI: 0000000000730370 RDI: 0000000000000003 RBP: 0000000000000000 R08: ffffffffffffffff R09: ffffffffffffffff R10: 00007ffdef5391a0 R11: 0000000000000293 R12: 0000000000000008 R13: 0000000000043dfc R14: 0000000000000168 R15: badc0ffeebadface INFO: task syz-executor1:15702 blocked for more than 140 seconds. Not tainted 4.14.71+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D26240 15702 1841 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5085 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common_io.constprop.2+0x266/0x3e0 kernel/sched/completion.c:129 submit_bio_wait+0x101/0x160 block/bio.c:954 blkdev_issue_flush+0x21a/0x310 block/blk-flush.c:531 ext4_sync_file+0xa7e/0x1050 fs/ext4/fsync.c:157 vfs_fsync_range+0x105/0x260 fs/sync.c:196 SYSC_msync mm/msync.c:90 [inline] SyS_msync+0x298/0x3b0 mm/msync.c:32 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007f7a35a5ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000001a RAX: ffffffffffffffda RBX: 00007f7a35a5b6d4 RCX: 0000000000457679 RDX: 0000000000000004 RSI: 087abbe8d1cc6ad9 RDI: 0000000020952000 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3e28 R14: 00000000004c2adf R15: 0000000000000000 INFO: task syz-executor1:15722 blocked for more than 140 seconds. Not tainted 4.14.71+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D28440 15722 1841 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5085 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common_io.constprop.2+0x266/0x3e0 kernel/sched/completion.c:129 submit_bio_wait+0x101/0x160 block/bio.c:954 blkdev_issue_flush+0x21a/0x310 block/blk-flush.c:531 ext4_sync_file+0xa7e/0x1050 fs/ext4/fsync.c:157 vfs_fsync_range+0x105/0x260 fs/sync.c:196 SYSC_msync mm/msync.c:90 [inline] SyS_msync+0x298/0x3b0 mm/msync.c:32 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007f7a35a18c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001a RAX: ffffffffffffffda RBX: 00007f7a35a196d4 RCX: 0000000000457679 RDX: 0000000000000004 RSI: 087abbe8d1cc6ad9 RDI: 0000000020952000 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3e28 R14: 00000000004c2adf R15: 0000000000000002 INFO: task syz-executor3:15723 blocked for more than 140 seconds. Not tainted 4.14.71+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D29688 15723 1842 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893 dev_ioctl+0x281/0xce0 net/core/dev_ioctl.c:421 sock_do_ioctl+0x92/0xb0 net/socket.c:980 sock_ioctl+0x263/0x430 net/socket.c:1070 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007efe4c5c9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007efe4c5ca6d4 RCX: 0000000000457679 RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000004 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d06c0 R14: 00000000004c06ca R15: 0000000000000000 INFO: task syz-executor3:15728 blocked for more than 140 seconds. Not tainted 4.14.71+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D29688 15728 1842 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893 dev_ioctl+0x281/0xce0 net/core/dev_ioctl.c:421 sock_do_ioctl+0x92/0xb0 net/socket.c:980 sock_ioctl+0x263/0x430 net/socket.c:1070 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007efe4c5a8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007efe4c5a96d4 RCX: 0000000000457679 RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000006 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d06c0 R14: 00000000004c06ca R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541 4 locks held by kworker/u4:1/64: #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x787/0x15c0 kernel/workqueue.c:2085 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x7bf/0x15c0 kernel/workqueue.c:2089 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x14c/0x880 net/core/net_namespace.c:449 #3: (rtnl_mutex){+.+.}, at: [] cleanup_net+0x151/0x880 net/core/net_namespace.c:452 1 lock held by rsyslogd/1626: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xa2/0xc0 fs/file.c:768 2 locks held by getty/1754: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor1/4597: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor3/7149: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/7810: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor3/9136: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor3/9165: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/9210: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/10953: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor0/12362: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/13699: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor0/14289: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/14492: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/15168: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor0/15443: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor3/15483: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 1 lock held by syz-executor1/15690: #0: (sb_internal){.+.+}, at: [] sb_start_intwrite include/linux/fs.h:1590 [inline] #0: (sb_internal){.+.+}, at: [] ext4_evict_inode+0x367/0x1520 fs/ext4/inode.c:250 2 locks held by syz-executor5/15693: #0: (rtnl_mutex){+.+.}, at: [] ppp_release+0xd9/0x1a0 drivers/net/ppp/ppp_generic.c:406 #1: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:138 [inline] #1: (cpu_hotplug_lock.rw_sem){++++}, at: [] flush_all_backlogs net/core/dev.c:4631 [inline] #1: (cpu_hotplug_lock.rw_sem){++++}, at: [] rollback_registered_many+0x416/0xac0 net/core/dev.c:7168 1 lock held by syz-executor3/15723: #0: (rtnl_mutex){+.+.}, at: [] dev_ioctl+0x281/0xce0 net/core/dev_ioctl.c:421 1 lock held by syz-executor3/15728: #0: (rtnl_mutex){+.+.}, at: [] dev_ioctl+0x281/0xce0 net/core/dev_ioctl.c:421 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.71+ #8 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x574/0xa70 kernel/hung_task.c:252 kthread+0x348/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15662 Comm: syz-executor4 Not tainted 4.14.71+ #8 task: ffff88019e82c680 task.stack: ffff88019f1d0000 RIP: 0010:inb arch/x86/include/asm/io.h:309 [inline] RIP: 0010:io_serial_in+0x60/0x80 drivers/tty/serial/8250/8250_port.c:450 RSP: 0000:ffff8801d76078f0 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffffac71d998 RBP: ffffffffac71d960 R08: 1ffffffff5785d01 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000020 R13: fffffbfff58e3b72 R14: fffffbfff58e3b35 R15: ffffffffac71db92 FS: 00007f706660a700(0000) GS:ffff8801d7600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004cc6d0 CR3: 00000001ccc04002 CR4: 00000000001606b0 DR0: 0001000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: serial_in drivers/tty/serial/8250/8250.h:115 [inline] wait_for_xmitr+0x90/0x1e0 drivers/tty/serial/8250/8250_port.c:2032 serial8250_console_putchar+0x19/0x50 drivers/tty/serial/8250/8250_port.c:3184 uart_console_write+0x4b/0xd0 drivers/tty/serial/serial_core.c:1883 serial8250_console_write+0x51b/0x800 drivers/tty/serial/8250/8250_port.c:3250 call_console_drivers kernel/printk/printk.c:1574 [inline] console_unlock+0x5b9/0xb50 kernel/printk/printk.c:2242 vprintk_emit+0x112/0x150 kernel/printk/printk.c:1766 vprintk_func+0x58/0x159 kernel/printk/printk_safe.c:401 printk+0xa7/0xcf kernel/printk/printk.c:1838 wq_watchdog_timer_fn.cold.24+0x4b/0x70 kernel/workqueue.c:5473 call_timer_fn+0x163/0x6a0 kernel/time/timer.c:1279 expire_timers+0x1f3/0x4a0 kernel/time/timer.c:1318 __run_timers kernel/time/timer.c:1634 [inline] run_timer_softirq+0x3a5/0x560 kernel/time/timer.c:1649 __do_softirq+0x215/0x997 kernel/softirq.c:288 invoke_softirq kernel/softirq.c:368 [inline] irq_exit+0x10f/0x150 kernel/softirq.c:409 exiting_irq arch/x86/include/asm/apic.h:648 [inline] smp_apic_timer_interrupt+0x188/0x5f0 arch/x86/kernel/apic/apic.c:1064 apic_timer_interrupt+0x84/0x90 arch/x86/entry/entry_64.S:787 RIP: 0033:0x401574 RSP: 002b:00007f7066609690 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff10 RAX: 000000003315e36d RBX: 0000000000000007 RCX: 0000000000457679 RDX: 0000000000000000 RSI: 00007f70666096c0 RDI: 0000000000000007 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d7950 R14: 00000000004c48c6 R15: 0000000000000000 Code: 30 0f b6 8d d1 00 00 00 48 8d 7d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 13 03 5d 38 89 da ec <0f> b6 c0 5b 5d c3 e8 15 df 7d ff eb c9 e8 3e df 7d ff eb e6 66