INFO: task syz-executor.5:18833 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D26672 18833 7603 0x80004006 Call Trace: context_switch kernel/sched/core.c:3378 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4094 schedule+0x188/0x220 kernel/sched/core.c:4168 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1532 unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 inode_lock include/linux/fs.h:792 [inline] __sock_release net/socket.c:604 [inline] sock_close+0x94/0x260 net/socket.c:1283 bcm_release+0x77/0x800 net/can/bcm.c:1474 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:176 [inline] __down_write kernel/locking/rwsem.c:1391 [inline] down_write+0xcd/0x130 kernel/locking/rwsem.c:1532 __sock_release net/socket.c:605 [inline] sock_close+0xd8/0x260 net/socket.c:1283 sock_mmap+0x90/0x90 net/socket.c:1278 __fput+0x2de/0x730 fs/file_table.c:280 task_work_run+0x147/0x1d0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5ef/0x1f80 kernel/exit.c:793 do_group_exit+0x15e/0x2c0 kernel/exit.c:891 get_signal+0x13cf/0x1d60 kernel/signal.c:2739 do_signal+0x33/0x610 arch/x86/kernel/signal.c:784 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:148 [inline] prepare_exit_to_usermode+0x280/0x600 arch/x86/entry/common.c:196 exit_to_usermode_loop arch/x86/entry/common.c:161 [inline] prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:196 syscall_return_slowpath+0xf9/0x420 arch/x86/entry/common.c:278 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Showing all locks held in the system: 3 locks held by kworker/u4:4/508: #0: ffff88821b02a938 ((wq_completion)netns){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff88821b02a938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc90002427d80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff895a5bf0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:565 1 lock held by khungtaskd/1135: #0: ffffffff892e6710 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 1 lock held by in:imklog/6684: #0: ffff88809ecb3130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x25d/0x2f0 fs/file.c:826 2 locks held by syz-executor.5/18833: #0: ffff888032730210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:792 [inline] #0: ffff888032730210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: __sock_release net/socket.c:604 [inline] #0: ffff888032730210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: sock_close+0x94/0x260 net/socket.c:1283 #1: ffffffff895a5bf0 (pernet_ops_rwsem){++++}-{3:3}, 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-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+0x353/0x380 kernel/kthread.c:268 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 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: 8367 Comm: kworker/u4:5 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:hlock_class kernel/locking/lockdep.c:179 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4043 [inline] RIP: 0010:__lock_acquire+0x75d/0x2b90 kernel/locking/lockdep.c:4294 Code: 41 8b 1e 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 70 88 12 8b be 08 00 00 00 e8 fb b8 57 00 48 0f a3 1d a3 6a b8 09 <72> 31 48 ba 00 00 00 00 00 fc ff df 41 0f b6 44 15 00 84 c0 0f 85 RSP: 0018:ffffc9001712f9e0 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000622 RCX: ffffffff815a1dc5 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b128930 RBP: ffffc9001712fb48 R08: dffffc0000000000 R09: fffffbfff1625127 R10: fffffbfff1625127 R11: 0000000000000000 R12: 0000000000000004 R13: 1ffffffff16a6c16 R14: ffff88803e326ac8 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2e6e30000 CR3: 00000000942ab000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_held_locks kernel/locking/lockdep.c:3628 [inline] __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x4a4/0x8a0 kernel/locking/lockdep.c:3702 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x6f/0xd0 kernel/locking/spinlock.c:191 lock_acquire+0x169/0x480 kernel/locking/lockdep.c:4923 rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:207 rcu_lock_release+0x5/0x20 include/linux/rcupdate.h:212 batadv_nc_process_nc_paths+0x390/0x390 net/batman-adv/network-coding.c:682 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:208 rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:207 rcu_read_lock include/linux/rcupdate.h:601 [inline] batadv_nc_process_nc_paths+0xb6/0x390 net/batman-adv/network-coding.c:686 batadv_nc_worker+0x3fc/0x5e0 net/batman-adv/network-coding.c:727 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2266 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2412 kthread+0x353/0x380 kernel/kthread.c:268 rcu_lock_release+0x20/0x20 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352