INFO: task syz-executor.4:20032 blocked for more than 143 seconds. Not tainted 5.11.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:24176 pid:20032 ppid: 8485 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0xa4d/0xf80 kernel/sched/core.c:5064 schedule+0x14b/0x200 kernel/sched/core.c:5143 rwsem_down_write_slowpath+0xe52/0x1590 kernel/locking/rwsem.c:1106 __down_write_common kernel/locking/rwsem.c:1261 [inline] __down_write kernel/locking/rwsem.c:1270 [inline] down_write+0x160/0x170 kernel/locking/rwsem.c:1407 unregister_netdevice_notifier+0x8e/0x430 net/core/dev.c:1868 isotp_release+0x22a/0x670 net/can/isotp.c:1016 __sock_release net/socket.c:597 [inline] sock_close+0xd8/0x260 net/socket.c:1256 __fput+0x34d/0x7a0 fs/file_table.c:280 task_work_run+0x137/0x1c0 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0x769/0x2490 kernel/exit.c:825 do_group_exit+0x168/0x2d0 kernel/exit.c:922 get_signal+0x16e5/0x2070 kernel/signal.c:2773 arch_do_signal_or_restart+0x8e/0x6a0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0xac/0x1e0 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x48/0x190 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e219 RSP: 002b:00007efddb37bc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000004 RBX: 0000000000000003 RCX: 000000000045e219 RDX: 0000000000000006 RSI: 0000000000000002 RDI: 000000000000001d RBP: 000000000119c068 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c034 R13: 00007ffd40a0016f R14: 00007efddb37c9c0 R15: 000000000119c034 Showing all locks held in the system: 3 locks held by kworker/u4:4/215: 1 lock held by khungtaskd/1648: #0: ffffffff8c311580 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151 1 lock held by in:imklog/8160: #0: ffff888012f19c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:947 2 locks held by syz-executor.4/20032: #0: ffff88806a672190 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff88806a672190 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release net/socket.c:596 [inline] #0: ffff88806a672190 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: sock_close+0x94/0x260 net/socket.c:1256 #1: ffffffff8d2e3070 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x8e/0x430 net/core/dev.c:1868 1 lock held by syz-executor.5/20556: #0: ffffffff8d2e3070 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x378/0x5e0 net/core/net_namespace.c:479 1 lock held by syz-executor.0/20558: #0: ffffffff8d2e3070 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x378/0x5e0 net/core/net_namespace.c:479 1 lock held by syz-executor.4/20571: #0: ffffffff8d2e3070 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x378/0x5e0 net/core/net_namespace.c:479 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1648 Comm: khungtaskd Not tainted 5.11.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x183/0x22e lib/dump_stack.c:120 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xce9/0xd30 kernel/hung_task.c:294 kthread+0x39a/0x3c0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 215 Comm: kworker/u4:4 Not tainted 5.11.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:84 [inline] RIP: 0010:lockdep_softirqs_off+0x76/0x410 kernel/locking/lockdep.c:4254 Code: 00 21 5f 81 4c 8d 74 24 20 49 c1 ee 03 48 b8 f1 f1 f1 f1 00 f3 f3 f3 4b 89 04 2e 48 c7 c0 04 c7 73 8d 48 c1 e8 03 42 8a 04 28 <84> c0 0f 85 2f 02 00 00 83 3d 7f a5 14 0c 00 0f 84 62 01 00 00 65 RSP: 0018:ffffc9000188f8c0 EFLAGS: 00000803 RAX: 1ffffffff1ae7800 RBX: 0000000000000200 RCX: ffff88801221d340 RDX: 0000000000000000 RSI: 0000000000000200 RDI: ffffffff880a7645 RBP: ffffc9000188f970 R08: dffffc0000000000 R09: fffffbfff1e54092 R10: fffffbfff1e54092 R11: 0000000000000000 R12: 1ffff92000311f34 R13: dffffc0000000000 R14: 1ffff92000311f1c R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe33e6d0000 CR3: 0000000018f2c000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __local_bh_disable_ip+0xbb/0x160 kernel/softirq.c:136 get_next_corpse net/netfilter/nf_conntrack_core.c:2198 [inline] nf_ct_iterate_cleanup+0x235/0x570 net/netfilter/nf_conntrack_core.c:2244 nf_conntrack_cleanup_net_list+0x7c/0x210 net/netfilter/nf_conntrack_core.c:2431 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x7ec/0xc60 net/core/net_namespace.c:604 process_one_work+0x833/0x10c0 kernel/workqueue.c:2275 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2421 kthread+0x39a/0x3c0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296