============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- syz-executor.5/9821 is trying to acquire lock: 000000004e6d6c6b (&type->i_mutex_dir_key#8){++++}, at: inode_lock include/linux/fs.h:748 [inline] 000000004e6d6c6b (&type->i_mutex_dir_key#8){++++}, at: fuse_reverse_inval_entry+0x2e1/0x660 fs/fuse/dir.c:1006 but task is already holding lock: 00000000771f68fd (&type->i_mutex_dir_key#8){++++}, at: inode_lock include/linux/fs.h:748 [inline] 00000000771f68fd (&type->i_mutex_dir_key#8){++++}, at: fuse_reverse_inval_entry+0xaa/0x660 fs/fuse/dir.c:987 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&type->i_mutex_dir_key#8); lock(&type->i_mutex_dir_key#8); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor.5/9821: #0: 000000007ecf0bbc (&fc->killsb){.+.+}, at: fuse_notify_delete fs/fuse/dev.c:1582 [inline] #0: 000000007ecf0bbc (&fc->killsb){.+.+}, at: fuse_notify fs/fuse/dev.c:1819 [inline] #0: 000000007ecf0bbc (&fc->killsb){.+.+}, at: fuse_dev_do_write+0x2343/0x2bc0 fs/fuse/dev.c:1894 #1: 00000000771f68fd (&type->i_mutex_dir_key#8){++++}, at: inode_lock include/linux/fs.h:748 [inline] #1: 00000000771f68fd (&type->i_mutex_dir_key#8){++++}, at: fuse_reverse_inval_entry+0xaa/0x660 fs/fuse/dir.c:987 stack backtrace: CPU: 1 PID: 9821 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:1764 [inline] check_deadlock kernel/locking/lockdep.c:1808 [inline] validate_chain kernel/locking/lockdep.c:2404 [inline] __lock_acquire.cold+0x121/0x57e 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] fuse_reverse_inval_entry+0x2e1/0x660 fs/fuse/dir.c:1006 fuse_notify_delete fs/fuse/dev.c:1585 [inline] fuse_notify fs/fuse/dev.c:1819 [inline] fuse_dev_do_write+0x239e/0x2bc0 fs/fuse/dev.c:1894 fuse_dev_write+0x153/0x1e0 fs/fuse/dev.c:1978 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x51b/0x770 fs/read_write.c:487 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f12c619b5a9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f12c470e168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f12c62bbf80 RCX: 00007f12c619b5a9 RDX: 000000000000002c RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007f12c61f67b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe947ca54f R14: 00007f12c470e300 R15: 0000000000022000 L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. devpts: called with bogus options overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. devpts: called with bogus options overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. devpts: called with bogus options devpts: called with bogus options overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. hfs: dir_umask requires a value hfs: unable to parse mount options overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. hfs: dir_umask requires a value netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. hfs: unable to parse mount options ebt_limit: overflow, try lower: 2048/0 overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. hfs: dir_umask requires a value hfs: unable to parse mount options ebt_limit: overflow, try lower: 2048/0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. hfs: dir_umask requires a value hfs: unable to parse mount options ebt_limit: overflow, try lower: 2048/0 ebt_limit: overflow, try lower: 2048/0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.