INFO: task syz-executor0:5188 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-executor0 D26104 5188 1846 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 unregister_netdevice_many+0x43/0x210 net/core/dev.c:8231 rtnl_newlink+0x1390/0x16d0 net/core/rtnetlink.c:2734 rtnetlink_rcv_msg+0x3bb/0xb30 net/core/rtnetlink.c:4255 netlink_rcv_skb+0x130/0x390 net/netlink/af_netlink.c:2432 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline] netlink_unicast+0x46d/0x620 net/netlink/af_netlink.c:1312 netlink_sendmsg+0x664/0xbe0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:645 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:655 ___sys_sendmsg+0x741/0x890 net/socket.c:2061 __sys_sendmsg+0xca/0x170 net/socket.c:2095 SYSC_sendmsg net/socket.c:2106 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2102 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007f5a92bffc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5a92c006d4 RCX: 0000000000457679 RDX: 0000000000040884 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d5890 R14: 00000000004c39ba R15: 0000000000000000 INFO: task syz-executor0:5195 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-executor0 D29688 5195 1846 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:00007f5a92bdec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5a92bdf6d4 RCX: 0000000000457679 RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000005 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d0928 R14: 00000000004c06e5 R15: 0000000000000001 INFO: task syz-executor0:5214 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-executor0 D29016 5214 1846 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 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x31d/0xb30 net/core/rtnetlink.c:4250 netlink_rcv_skb+0x130/0x390 net/netlink/af_netlink.c:2432 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline] netlink_unicast+0x46d/0x620 net/netlink/af_netlink.c:1312 netlink_sendmsg+0x664/0xbe0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:645 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:655 ___sys_sendmsg+0x741/0x890 net/socket.c:2061 __sys_sendmsg+0xca/0x170 net/socket.c:2095 SYSC_sendmsg net/socket.c:2106 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2102 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457679 RSP: 002b:00007f5a92bbdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5a92bbe6d4 RCX: 0000000000457679 RDX: 0000000000040884 RSI: 00000000200000c0 RDI: 0000000000000006 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d5890 R14: 00000000004c39ba R15: 0000000000000002 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 2 locks held by getty/1766: #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 2 locks held by syz-executor0/5188: #0: (rtnl_mutex){+.+.}, at: [] rtnl_lock net/core/rtnetlink.c:72 [inline] #0: (rtnl_mutex){+.+.}, at: [] rtnetlink_rcv_msg+0x31d/0xb30 net/core/rtnetlink.c:4250 #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-executor0/5195: #0: (rtnl_mutex){+.+.}, at: [] dev_ioctl+0x281/0xce0 net/core/dev_ioctl.c:421 1 lock held by syz-executor0/5214: #0: (rtnl_mutex){+.+.}, at: [] rtnl_lock net/core/rtnetlink.c:72 [inline] #0: (rtnl_mutex){+.+.}, at: [] rtnetlink_rcv_msg+0x31d/0xb30 net/core/rtnetlink.c:4250 ============================================= 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: 5097 Comm: syz-executor3 Not tainted 4.14.71+ #8 task: ffff8801c7fbde00 task.stack: ffff8801c9af8000 RIP: 0033:0x401574 RSP: 002b:00007f4163ad1690 EFLAGS: 00000206 RAX: 0000000005f1e481 RBX: 0000000000000007 RCX: 0000000000457679 RDX: 0000000000000000 RSI: 00007f4163ad16c0 RDI: 0000000000000007 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d7cf0 R14: 00000000004c49b7 R15: 0000000000000000 FS: 00007f4163ad2700(0000) GS:ffff8801dba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000010cbb20 CR3: 00000001c9370005 CR4: 00000000001606b0