INFO: task syz-executor.4:29393 blocked for more than 143 seconds. Not tainted 5.11.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:28728 pid:29393 ppid: 8415 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4324 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5075 schedule+0xcf/0x270 kernel/sched/core.c:5154 rwsem_down_write_slowpath+0x7e5/0x1200 kernel/locking/rwsem.c:1106 __down_write_common kernel/locking/rwsem.c:1261 [inline] __down_write_common kernel/locking/rwsem.c:1258 [inline] __down_write kernel/locking/rwsem.c:1270 [inline] down_write+0x137/0x150 kernel/locking/rwsem.c:1407 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1891 bcm_release+0x94/0x750 net/can/bcm.c:1472 __sock_release+0xcd/0x280 net/socket.c:599 sock_close+0x18/0x20 net/socket.c:1258 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc61/0x2ae0 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x42c/0x2100 kernel/signal.c:2773 arch_do_signal_or_restart+0x2a8/0x1eb0 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+0x148/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x465ef9 RSP: 002b:00007fd77146f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000003 RBX: 000000000056bf60 RCX: 0000000000465ef9 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 00000000004bcd1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007fff27cd004f R14: 00007fd77146f300 R15: 0000000000022000 Showing all locks held in the system: 2 locks held by kworker/u4:3/129: #0: ffff8880b9d35198 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1321 [inline] #0: ffff8880b9d35198 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x21a0 kernel/sched/core.c:4992 #1: ffff8880b9d1f948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 4 locks held by kworker/u4:4/194: 1 lock held by khungtaskd/1664: #0: ffffffff8bf743a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6327 1 lock held by in:imklog/8075: #0: ffff888015370870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:961 2 locks held by syz-executor.4/29393: #0: ffff88817edde190 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:775 [inline] #0: ffff88817edde190 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:598 #1: ffffffff8d665890 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1891 1 lock held by syz-executor.4/29802: #0: ffffffff8d665890 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:470 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1664 Comm: khungtaskd Not tainted 5.11.0-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+0xfa/0x151 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 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+0xd48/0xfb0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 29609 Comm: kworker/1:143 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: 0x0 (events) RIP: 0010:rcu_is_watching+0x86/0xc0 kernel/rcu/tree.c:1170 Code: c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1f 8b 83 48 01 00 00 d1 e8 83 e0 01 65 ff 0d ca 45 a2 7e <74> 03 5b 5d c3 e8 3f 9b a0 ff 5b 5d c3 e8 a8 81 57 00 eb da e8 b1 RSP: 0018:ffffc90019547cb0 EFLAGS: 00000082 RAX: 0000000000000001 RBX: ffff8880b9d35fc0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffff8880b9d36108 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff83bf59c4 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888021070988 R14: ffff888021070988 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f38395ed020 CR3: 0000000015b50000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_sched_held+0x1c/0x70 kernel/rcu/update.c:123 trace_prandom_u32 include/trace/events/random.h:310 [inline] prandom_u32+0x3b8/0x470 lib/random32.c:389 __lock_pin_lock kernel/locking/lockdep.c:5282 [inline] lock_pin_lock+0x1a3/0x2b0 kernel/locking/lockdep.c:5570 rq_pin_lock kernel/sched/sched.h:1244 [inline] rq_lock kernel/sched/sched.h:1322 [inline] __schedule+0x22b/0x21a0 kernel/sched/core.c:4992 schedule+0xcf/0x270 kernel/sched/core.c:5154 worker_thread+0x14c/0x1120 kernel/workqueue.c:2442 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294