IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready ====================================================== WARNING: possible circular locking dependency detected 4.19.163-syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/14 is trying to acquire lock: 00000000174c47ec (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] 00000000174c47ec (&sb->s_type->i_mutex_key#11){+.+.}, at: __sock_release+0x7d/0x290 net/socket.c:578 but task is already holding lock: 00000000751ac35c ((delayed_fput_work).work){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ((delayed_fput_work).work){+.+.}: process_one_work+0x7e3/0x1670 kernel/workqueue.c:2131 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #2 ((wq_completion)"events"){+.+.}: flush_workqueue+0xf2/0x13c0 kernel/workqueue.c:2663 flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x37/0x60 net/tipc/core.c:100 ops_exit_list.isra.5+0x8b/0x120 net/core/net_namespace.c:153 cleanup_net+0x368/0x850 net/core/net_namespace.c:553 process_one_work+0x830/0x1670 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #1 (pernet_ops_rwsem){++++}: down_write+0x38/0x90 kernel/locking/rwsem.c:70 unregister_netdevice_notifier+0x79/0x320 net/core/dev.c:1708 bcm_release+0x86/0x500 net/can/bcm.c:1525 __sock_release+0xc2/0x290 net/socket.c:579 sock_close+0x10/0x20 net/socket.c:1140 __fput+0x249/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x1a9/0x200 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sb->s_type->i_mutex_key#11){+.+.}: lock_acquire+0x173/0x3d0 kernel/locking/lockdep.c:3907 down_write+0x38/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x7d/0x290 net/socket.c:578 sock_close+0x10/0x20 net/socket.c:1140 __fput+0x249/0x7f0 fs/file_table.c:278 delayed_fput+0x4b/0x70 fs/file_table.c:304 process_one_work+0x830/0x1670 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#11 --> (wq_completion)"events" --> (delayed_fput_work).work Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((delayed_fput_work).work); lock((wq_completion)"events"); lock((delayed_fput_work).work); lock(&sb->s_type->i_mutex_key#11); *** DEADLOCK *** 2 locks held by kworker/0:1/14: #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000001b199c8e ((wq_completion)"events"){+.+.}, at: process_one_work+0x762/0x1670 kernel/workqueue.c:2126 #1: 00000000751ac35c ((delayed_fput_work).work){+.+.}, at: process_one_work+0x792/0x1670 kernel/workqueue.c:2130 stack backtrace: CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.163-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events delayed_fput Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x177 lib/dump_stack.c:118 print_circular_bug.isra.34.cold.55+0x1bd/0x27d kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x30df/0x4980 kernel/locking/lockdep.c:3415 lock_acquire+0x173/0x3d0 kernel/locking/lockdep.c:3907 down_write+0x38/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x7d/0x290 net/socket.c:578 sock_close+0x10/0x20 net/socket.c:1140 __fput+0x249/0x7f0 fs/file_table.c:278 delayed_fput+0x4b/0x70 fs/file_table.c:304 process_one_work+0x830/0x1670 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 7552 at net/kcm/kcmsock.c:629 kcm_write_msgs.cold.34+0x5f/0x13e net/kcm/kcmsock.c:629