INFO: task syz-executor.4:6914 blocked for more than 140 seconds. Not tainted 4.19.161-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28392 6914 8138 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x4f/0x90 kernel/locking/rwsem.c:72 register_netdevice_notifier+0x7b/0x5b0 net/core/dev.c:1639 raw_init+0x296/0x340 net/can/raw.c:343 can_create+0x27c/0x470 net/can/af_can.c:184 __sock_create+0x3d8/0x740 net/socket.c:1276 sock_create net/socket.c:1316 [inline] __sys_socket+0xef/0x200 net/socket.c:1346 __do_sys_socket net/socket.c:1355 [inline] __se_sys_socket net/socket.c:1353 [inline] __x64_sys_socket+0x6f/0xb0 net/socket.c:1353 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45deb9 Code: Bad RIP value. RSP: 002b:00007f2d58956c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000034480 RCX: 000000000045deb9 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000000000000001d RBP: 000000000119bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf2c R13: 00007ffd75ec4bdf R14: 00007f2d589579c0 R15: 000000000119bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1566: #0: 0000000029cba13f (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440 1 lock held by in:imklog/7808: #0: 0000000010bce911 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 3 locks held by kworker/u4:6/9554: 1 lock held by syz-executor.4/6914: #0: 00000000a6a93e26 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7b/0x5b0 net/core/dev.c:1639 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1566 Comm: khungtaskd Not tainted 4.19.161-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+0x1fc/0x2fe lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9554 Comm: kworker/u4:6 Not tainted 4.19.161-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0xc/0x12 Code: 56 57 41 50 41 51 41 52 41 53 e8 8f 14 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 c3 66 90 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <3c> 01 75 02 5a c3 56 0f b6 f0 e8 c5 ff ff ff 5e 5a c3 66 90 48 b8 RSP: 0018:ffff888095b27b40 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 000000000000e13d RCX: ffffffff814d6460 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff89e5cd10 RBP: ffffffff89e5cd10 R08: 0000000000000000 R09: fffffbfff13cb9a2 R10: ffffffff89e5cd13 R11: 0000000000000000 R12: ffffffff89e5cd18 R13: ffffffff89e5cd20 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055acdc8a8d10 CR3: 00000000a932f000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:684 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:58 [inline] do_raw_spin_unlock+0x171/0x230 kernel/locking/spinlock_debug.c:135 __raw_spin_unlock include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock+0x1f/0x40 kernel/locking/spinlock.c:176 spin_unlock include/linux/spinlock.h:369 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:1927 [inline] nf_ct_iterate_cleanup+0x223/0x520 net/netfilter/nf_conntrack_core.c:1951 nf_conntrack_cleanup_net_list+0x7e/0x250 net/netfilter/nf_conntrack_core.c:2138 ops_exit_list+0xf9/0x150 net/core/net_namespace.c:156 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415