INFO: task syz-executor.0:23466 blocked for more than 143 seconds. Not tainted 5.6.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26760 23466 7041 0x80004006 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x7c9/0xc50 kernel/sched/core.c:4080 schedule+0x188/0x220 kernel/sched/core.c:4154 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1238 __down_write kernel/locking/rwsem.c:1392 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1535 unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 inode_lock include/linux/fs.h:792 [inline] __sock_release net/socket.c:604 [inline] sock_close+0x94/0x260 net/socket.c:1283 raw_release+0x5f/0x770 net/can/raw.c:354 atomic64_set include/asm-generic/atomic-instrumented.h:854 [inline] atomic_long_set include/asm-generic/atomic-long.h:40 [inline] rwsem_set_owner kernel/locking/rwsem.c:177 [inline] __down_write kernel/locking/rwsem.c:1394 [inline] down_write+0xcd/0x130 kernel/locking/rwsem.c:1535 __sock_release net/socket.c:605 [inline] sock_close+0xd8/0x260 net/socket.c:1283 sock_mmap+0x90/0x90 net/socket.c:1278 __fput+0x2d8/0x730 fs/file_table.c:280 task_work_run+0x176/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5ef/0x1f80 kernel/exit.c:801 do_group_exit+0x15e/0x2c0 kernel/exit.c:899 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 get_signal+0x13cf/0x1d60 kernel/signal.c:2739 alloc_file+0x86/0x4b0 fs/file_table.c:197 do_signal+0x33/0x610 arch/x86/kernel/signal.c:813 rcu_read_unlock_sched include/linux/rcupdate.h:732 [inline] __fd_install+0x251/0x490 fs/file.c:613 exit_to_usermode_loop arch/x86/entry/common.c:160 [inline] prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:195 syscall_return_slowpath+0xf9/0x420 arch/x86/entry/common.c:277 entry_SYSCALL_64_after_hwframe+0x49/0xbe Showing all locks held in the system: 3 locks held by kworker/u4:2/67: #0: ffff8880a9b73d28 ((wq_completion)netns){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880a9b73d28 ((wq_completion)netns){+.+.}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc90000ff7d88 (net_cleanup_work){+.+.}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff8938efa8 (pernet_ops_rwsem){++++}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:551 1 lock held by khungtaskd/1135: #0: ffffffff890d9ac8 (rcu_read_lock){....}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 2 locks held by in:imklog/6577: #0: ffff88809fb99860 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:826 #1: ffff8880ae837198 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1215 [inline] #1: ffff8880ae837198 (&rq->lock){-.-.}, at: __schedule+0xd7/0xc50 kernel/sched/core.c:4028 2 locks held by syz-executor.0/23466: #0: ffff88808d633c80 (&sb->s_type->i_mutex_key#14){+.+.}, at: inode_lock include/linux/fs.h:792 [inline] #0: ffff88808d633c80 (&sb->s_type->i_mutex_key#14){+.+.}, at: __sock_release net/socket.c:604 [inline] #0: ffff88808d633c80 (&sb->s_type->i_mutex_key#14){+.+.}, at: sock_close+0x94/0x260 net/socket.c:1283 #1: ffffffff8938efa8 (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1135 Comm: khungtaskd Not tainted 5.6.0-rc7-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+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x317/0x340 kernel/kthread.c:255 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 145 Comm: kworker/u4:3 Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:debug_lockdep_rcu_enabled+0x38/0xe0 kernel/rcu/update.c:251 Code: e8 03 49 bf 00 00 00 00 00 fc ff df 42 8a 04 38 84 c0 75 57 31 db 83 3d a1 57 e8 07 00 74 44 48 c7 c0 40 ea 49 89 48 c1 e8 03 <42> 8a 04 38 84 c0 75 58 83 3d 29 88 e8 07 00 74 28 65 4c 8b 34 25 RSP: 0018:ffffc900014c7ba8 EFLAGS: 00000806 RAX: 1ffffffff1293d48 RBX: 0000000000000000 RCX: ffffffff815a05d9 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8949b8a0 RBP: ffff8880a9314480 R08: dffffc0000000000 R09: fffffbfff1293715 R10: fffffbfff1293715 R11: 0000000000000000 R12: 0000000000000282 R13: dffffc0000000000 R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f925defb000 CR3: 00000000a41a0000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_release+0x137/0x1a0 include/trace/events/lock.h:58 lock_release+0xe8/0x720 kernel/locking/lockdep.c:4501 check_preemption_disabled+0x40/0x240 lib/smp_processor_id.c:16 rcu_lock_release+0x5/0x20 include/linux/rcupdate.h:212 rcu_read_unlock include/linux/rcupdate.h:655 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:411 [inline] batadv_nc_worker+0x261/0x5e0 net/batman-adv/network-coding.c:718 lock_is_held include/linux/lockdep.h:361 [inline] rcu_read_lock_sched_held+0x106/0x170 kernel/rcu/update.c:121 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2266 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0xfe/0x800 kernel/locking/spinlock_debug.c:113 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2412 kthread+0x317/0x340 kernel/kthread.c:255 rcu_lock_release+0x20/0x20 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352