============================================ WARNING: possible recursive locking detected 4.14.243-syzkaller #0 Not tainted -------------------------------------------- syz-executor847/7985 is trying to acquire lock: (&type->i_mutex_dir_key#7){++++}, at: [] inode_lock include/linux/fs.h:719 [inline] (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x2a3/0x5e0 fs/fuse/dir.c:991 but task is already holding lock: (&type->i_mutex_dir_key#7){++++}, at: [] inode_lock include/linux/fs.h:719 [inline] (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x99/0x5e0 fs/fuse/dir.c:972 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&type->i_mutex_dir_key#7); lock(&type->i_mutex_dir_key#7); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor847/7985: #0: (&fc->killsb){.+.+}, at: [] fuse_notify_delete fs/fuse/dev.c:1575 [inline] #0: (&fc->killsb){.+.+}, at: [] fuse_notify fs/fuse/dev.c:1812 [inline] #0: (&fc->killsb){.+.+}, at: [] fuse_dev_do_write+0x1ec7/0x25c0 fs/fuse/dev.c:1887 #1: (&type->i_mutex_dir_key#7){++++}, at: [] inode_lock include/linux/fs.h:719 [inline] #1: (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x99/0x5e0 fs/fuse/dir.c:972 stack backtrace: CPU: 0 PID: 7985 Comm: syz-executor847 Not tainted 4.14.243-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_deadlock_bug kernel/locking/lockdep.c:1800 [inline] check_deadlock kernel/locking/lockdep.c:1847 [inline] validate_chain kernel/locking/lockdep.c:2448 [inline] __lock_acquire.cold+0x180/0x97c kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:719 [inline] fuse_reverse_inval_entry+0x2a3/0x5e0 fs/fuse/dir.c:991 fuse_notify_delete fs/fuse/dev.c:1578 [inline] fuse_notify fs/fuse/dev.c:1812 [inline] fuse_dev_do_write+0x1f22/0x25c0 fs/fuse/dev.c:1887 fuse_dev_write+0x125/0x1a0 fs/fuse/dev.c:1971 call_write_iter include/linux/fs.h:1778 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x44c/0x630 fs/read_write.c:482 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4455e9 RSP: 002b:00007f89e31302f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000004ce4e0 RCX: 00000000004455e9 RDX: 000000000000002e RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 000000000049e0d4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049c0d0 R13: 65