wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 ====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 syz-executor.0/9593 is trying to acquire lock: 000000003da33c40 ((wq_completion)"dio/%s"sb->s_id){+.+.}, at: flush_workqueue+0xe8/0x13e0 kernel/workqueue.c:2658 but task is already holding lock: IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready 000000008b92d7b3 (&sb->s_type->i_mutex_key#10){+.+.}, at: inode_trylock include/linux/fs.h:768 [inline] 000000008b92d7b3 (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x21f/0xf20 fs/ext4/file.c:238 which lock already depends on the new lock. wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#10){+.+.}: inode_lock include/linux/fs.h:748 [inline] __generic_file_fsync+0xb0/0x1f0 fs/libfs.c:989 ext4_sync_file+0xa35/0x1420 fs/ext4/fsync.c:118 vfs_fsync_range+0x13a/0x220 fs/sync.c:197 generic_write_sync include/linux/fs.h:2750 [inline] dio_complete+0x763/0xac0 fs/direct-io.c:329 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 ((work_completion)(&dio->complete_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 -> #0 ((wq_completion)"dio/%s"sb->s_id){+.+.}: flush_workqueue+0x117/0x13e0 kernel/workqueue.c:2661 drain_workqueue+0x1a5/0x460 kernel/workqueue.c:2826 destroy_workqueue+0x75/0x790 kernel/workqueue.c:4183 sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634 do_blockdev_direct_IO fs/direct-io.c:1285 [inline] __blockdev_direct_IO+0x5f55/0xef40 fs/direct-io.c:1419 ext4_direct_IO_write fs/ext4/inode.c:3777 [inline] ext4_direct_IO+0xae4/0x1c50 fs/ext4/inode.c:3915 generic_file_direct_write+0x208/0x4a0 mm/filemap.c:3073 __generic_file_write_iter+0x2d0/0x610 mm/filemap.c:3252 wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 ext4_file_write_iter+0x2fe/0xf20 fs/ext4/file.c:272 call_write_iter include/linux/fs.h:1821 [inline] aio_write+0x37f/0x5c0 fs/aio.c:1574 __io_submit_one fs/aio.c:1858 [inline] io_submit_one+0xecd/0x20c0 fs/aio.c:1909 __do_sys_io_submit fs/aio.c:1953 [inline] __se_sys_io_submit+0x11b/0x4a0 fs/aio.c:1924 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 Chain exists of: (wq_completion)"dio/%s"sb->s_id --> (work_completion)(&dio->complete_work) --> &sb->s_type->i_mutex_key#10 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready lock((work_completion)(&dio->complete_work)); lock(&sb->s_type->i_mutex_key#10); lock((wq_completion)"dio/%s"sb->s_id); *** DEADLOCK *** 1 lock held by syz-executor.0/9593: #0: 000000008b92d7b3 (&sb->s_type->i_mutex_key#10){+.+.}, at: inode_trylock include/linux/fs.h:768 [inline] #0: 000000008b92d7b3 (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x21f/0xf20 fs/ext4/file.c:238 stack backtrace: IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready CPU: 1 PID: 9593 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 __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 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready 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 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 flush_workqueue+0x117/0x13e0 kernel/workqueue.c:2661 drain_workqueue+0x1a5/0x460 kernel/workqueue.c:2826 destroy_workqueue+0x75/0x790 kernel/workqueue.c:4183 sb_init_dio_done_wq+0x72/0x90 fs/direct-io.c:634 do_blockdev_direct_IO fs/direct-io.c:1285 [inline] __blockdev_direct_IO+0x5f55/0xef40 fs/direct-io.c:1419 ext4_direct_IO_write fs/ext4/inode.c:3777 [inline] ext4_direct_IO+0xae4/0x1c50 fs/ext4/inode.c:3915 generic_file_direct_write+0x208/0x4a0 mm/filemap.c:3073 __generic_file_write_iter+0x2d0/0x610 mm/filemap.c:3252 ext4_file_write_iter+0x2fe/0xf20 fs/ext4/file.c:272 call_write_iter include/linux/fs.h:1821 [inline] aio_write+0x37f/0x5c0 fs/aio.c:1574 __io_submit_one fs/aio.c:1858 [inline] io_submit_one+0xecd/0x20c0 fs/aio.c:1909 __do_sys_io_submit fs/aio.c:1953 [inline] __se_sys_io_submit+0x11b/0x4a0 fs/aio.c:1924 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f5272c3afe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f527238f168 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 00007f5272d4e030 RCX: 00007f5272c3afe9 RDX: 0000000020000540 RSI: 0000000000001801 RDI: 00007f5272d29000 RBP: 00007f5272c9508d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffa7c37cbf R14: 00007f527238f300 R15: 0000000000022000