INFO: task syz-executor.4:28622 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.4 D26064 28622 7478 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:797 [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+0x2ed/0x750 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:795 do_group_exit+0x15e/0x2c0 kernel/exit.c:893 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/u4:6/320: #0: ffff8880a9b79938 ((wq_completion)netns){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff8880a9b79938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc90001f07d80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff895a9330 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:565 1 lock held by khungtaskd/1139: #0: ffffffff892e6bd0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 2 locks held by syz-executor.4/28622: #0: ffff8882182a1210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:797 [inline] #0: ffff8882182a1210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: __sock_release net/socket.c:604 [inline] #0: ffff8882182a1210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: sock_close+0x94/0x260 net/socket.c:1283 #1: ffffffff895a9330 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1139 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: 4105 Comm: systemd-journal Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x607/0x1cf0 arch/x86/kernel/unwind_orc.c:420 Code: 00 00 00 00 fc ff df 43 8a 04 34 84 c0 0f 85 f2 0f 00 00 48 89 e8 48 c1 e8 03 42 8a 04 30 84 c0 0f 85 05 10 00 00 41 0f b7 07 <89> c3 83 e3 0f 66 85 db 0f 84 8c 00 00 00 8d 43 fe 83 f8 07 0f 87 RSP: 0018:ffffc90001607a08 EFLAGS: 00000246 RAX: 0000000000000015 RBX: ffffffff8981d7cc RCX: dffffc0000000000 RDX: ffffffff89e86562 RSI: ffffffff8981d7b0 RDI: ffffffff81328bbc RBP: ffffffff89e86567 R08: 0000000000000020 R09: ffffc90001607b78 R10: fffff520002c0f65 R11: 0000000000000000 R12: 1ffffffff13d0cac R13: ffffc90001607ad0 R14: dffffc0000000000 R15: ffffffff89e86566 FS: 00007f8071a2f8c0(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f806efa7000 CR3: 0000000092f27000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: getname fs/namei.c:209 [inline] user_path_create fs/namei.c:3502 [inline] do_mkdirat+0x3a/0x310 fs/namei.c:3640 stack_trace_save+0x150/0x150 kernel/stacktrace.c:124 arch_stack_walk+0xb4/0xe0 arch/x86/kernel/stacktrace.c:25 getname fs/namei.c:209 [inline] user_path_create fs/namei.c:3502 [inline] do_mkdirat+0x3a/0x310 fs/namei.c:3640 stack_trace_save+0xad/0x150 kernel/stacktrace.c:123 save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495 save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:586 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x1f5/0x2d0 mm/slab.c:3484 getname_flags+0xb8/0x610 fs/namei.c:138 getname fs/namei.c:209 [inline] user_path_create fs/namei.c:3502 [inline] do_mkdirat+0x3a/0x310 fs/namei.c:3640 lock_is_held include/linux/lockdep.h:406 [inline] rcu_read_lock_sched_held+0x106/0x170 kernel/rcu/update.c:121 lock_acquire+0x169/0x480 kernel/locking/lockdep.c:4923 pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:650 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:55 [inline] do_raw_spin_unlock+0x134/0x8d0 kernel/locking/spinlock_debug.c:139 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x24/0x40 kernel/locking/spinlock.c:183 cache_alloc_refill+0x3cf/0x3f0 mm/slab.c:2981 slab_alloc mm/slab.c:3313 [inline] kmem_cache_alloc+0x194/0x2d0 mm/slab.c:3484 getname_flags+0xb8/0x610 fs/namei.c:138 slab_post_alloc_hook mm/slab.h:586 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x1f5/0x2d0 mm/slab.c:3484 getname_flags+0xb8/0x610 fs/namei.c:138 syscall_trace_enter+0x614/0x8c0 arch/x86/entry/common.c:130 getname fs/namei.c:209 [inline] user_path_create fs/namei.c:3502 [inline] do_mkdirat+0x3a/0x310 fs/namei.c:3640 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x7f8070ceb687 Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd480680e8 EFLAGS: 00000293 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007ffd4806b150 RCX: 00007f8070ceb687 RDX: 0000000000000000 RSI: 00000000000001ed RDI: 000055a6b24098a0 RBP: 00007ffd48068120 R08: 000055a6b08093e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 000055a6b24098a0 R15: 00007ffd48068760