====================================================== WARNING: possible circular locking dependency detected 4.19.195-syzkaller #0 Not tainted ------------------------------------------------------ kworker/1:4/9380 is trying to acquire lock: 00000000c2b3b761 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] 00000000c2b3b761 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:578 but task is already holding lock: 000000001a06167a ((delayed_fput_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ((delayed_fput_work).work){+.+.}: worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #2 ((wq_completion)"events"){+.+.}: flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #1 (pernet_ops_rwsem){++++}: unregister_netdevice_notifier+0x7b/0x330 net/core/dev.c:1708 bcm_release+0x94/0x700 net/can/bcm.c:1525 __sock_release+0xcd/0x2a0 net/socket.c:579 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 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+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sb->s_type->i_mutex_key#13){+.+.}: down_write+0x34/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x86/0x2a0 net/socket.c:578 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 delayed_fput+0x56/0x70 fs/file_table.c:304 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 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#13 --> (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#13); *** DEADLOCK *** 2 locks held by kworker/1:4/9380: #0: 0000000032fdf371 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000001a06167a ((delayed_fput_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 stack backtrace: CPU: 1 PID: 9380 Comm: kworker/1:4 Not tainted 4.19.195-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+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 down_write+0x34/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x86/0x2a0 net/socket.c:578 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 delayed_fput+0x56/0x70 fs/file_table.c:304 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 netlink: 144 bytes leftover after parsing attributes in process `syz-executor.3'. EXT4-fs (loop5): invalid first ino: 0 netlink: 144 bytes leftover after parsing attributes in process `syz-executor.3'. EXT4-fs (loop5): invalid first ino: 0 netlink: 144 bytes leftover after parsing attributes in process `syz-executor.3'. EXT4-fs (loop5): unsupported inode size: 0 validate_nla: 5 callbacks suppressed netlink: 'syz-executor.3': attribute type 1 has an invalid length. EXT4-fs (loop5): blocksize: 1024 netlink: 144 bytes leftover after parsing attributes in process `syz-executor.3'. EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 netlink: 'syz-executor.3': attribute type 1 has an invalid length. netlink: 144 bytes leftover after parsing attributes in process `syz-executor.3'. EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 netlink: 'syz-executor.3': attribute type 1 has an invalid length. secmark_tg_check: 58 callbacks suppressed xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 EXT4-fs (loop5): unsupported inode size: 0 EXT4-fs (loop5): blocksize: 1024 EXT4-fs (loop5): VFS: Can't find ext4 filesystem EXT4-fs (loop5): VFS: Can't find ext4 filesystem EXT4-fs (loop5): VFS: Can't find ext4 filesystem tmpfs: No value for mount option 'permit_directio' EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue tmpfs: No value for mount option 'permit_directio' EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue tmpfs: No value for mount option 'permit_directio' tmpfs: No value for mount option 'permit_directio' EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue tmpfs: No value for mount option 'permit_directio' EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue secmark_tg_check: 76 callbacks suppressed xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 xt_SECMARK: mode already set to 1 cannot mix with rules for mode 0 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue