====================================================== WARNING: possible circular locking dependency detected 4.14.291-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/11994 is trying to acquire lock: (&oi->lock){+.+.}, at: [] ovl_nlink_start+0x22f/0x460 fs/overlayfs/util.c:523 but task is already holding lock: (sb_writers#6){.+.+}, at: [] sb_start_write include/linux/fs.h:1551 [inline] (sb_writers#6){.+.+}, at: [] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sb_writers#6){.+.+}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x64/0x260 fs/super.c:1342 sb_start_write include/linux/fs.h:1551 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538 lookup_open+0x77a/0x1750 fs/namei.c:3241 do_last fs/namei.c:3334 [inline] path_openat+0xe08/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}: down_read+0x36/0x80 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] lookup_slow+0x129/0x400 fs/namei.c:1674 lookup_one_len_unlocked+0x3a0/0x410 fs/namei.c:2595 ovl_lower_positive+0x184/0x350 fs/overlayfs/namei.c:783 ovl_rename+0x47c/0xe50 fs/overlayfs/dir.c:968 vfs_rename+0x560/0x1820 fs/namei.c:4498 SYSC_renameat2 fs/namei.c:4646 [inline] SyS_renameat2+0x95b/0xad0 fs/namei.c:4535 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&oi->lock){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 ovl_nlink_start+0x22f/0x460 fs/overlayfs/util.c:523 ovl_link+0xee/0x190 fs/overlayfs/dir.c:607 vfs_link+0x6d5/0xb40 fs/namei.c:4266 SYSC_linkat fs/namei.c:4334 [inline] SyS_linkat+0x3e5/0x6a0 fs/namei.c:4290 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &oi->lock --> &ovl_i_mutex_dir_key[depth]#2 --> sb_writers#6 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#6); lock(&ovl_i_mutex_dir_key[depth]#2); lock(sb_writers#6); lock(&oi->lock); *** DEADLOCK *** 4 locks held by syz-executor.4/11994: #0: (sb_writers#14){.+.+}, at: [] sb_start_write include/linux/fs.h:1551 [inline] #0: (sb_writers#14){.+.+}, at: [] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 #1: (&ovl_i_mutex_dir_key[depth]#2/1){+.+.}, at: [] inode_lock_nested include/linux/fs.h:754 [inline] #1: (&ovl_i_mutex_dir_key[depth]#2/1){+.+.}, at: [] filename_create+0x12a/0x3f0 fs/namei.c:3676 #2: (&ovl_i_mutex_key[depth]#2){+.+.}, at: [] inode_lock include/linux/fs.h:719 [inline] #2: (&ovl_i_mutex_key[depth]#2){+.+.}, at: [] vfs_link+0x553/0xb40 fs/namei.c:4257 #3: (sb_writers#6){.+.+}, at: [] sb_start_write include/linux/fs.h:1551 [inline] #3: (sb_writers#6){.+.+}, at: [] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 stack backtrace: CPU: 1 PID: 11994 Comm: syz-executor.4 Not tainted 4.14.291-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 ovl_nlink_start+0x22f/0x460 fs/overlayfs/util.c:523 ovl_link+0xee/0x190 fs/overlayfs/dir.c:607 vfs_link+0x6d5/0xb40 fs/namei.c:4266 SYSC_linkat fs/namei.c:4334 [inline] SyS_linkat+0x3e5/0x6a0 fs/namei.c:4290 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f59f5524279 RSP: 002b:00007f59f3e99168 EFLAGS: 00000246 ORIG_RAX: 0000000000000056 RAX: ffffffffffffffda RBX: 00007f59f5636f80 RCX: 00007f59f5524279 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000020000200 RBP: 00007f59f557e189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd9699fe7f R14: 00007f59f3e99300 R15: 0000000000022000 EXT4-fs (loop1): inodes count not valid: 7077920 vs 32 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 9pnet: Insufficient options for proto=fd F2FS-fs (loop4): Invalid log sectors per block(393219) log sectorsize(9) F2FS-fs (loop4): Can't find valid F2FS filesystem in 1th superblock F2FS-fs (loop4): invalid crc value F2FS-fs (loop4): Mounted with checkpoint version = 7ad43cd7 F2FS-fs (loop4): Invalid log sectors per block(393219) log sectorsize(9) F2FS-fs (loop4): Can't find valid F2FS filesystem in 1th superblock F2FS-fs (loop4): invalid crc value F2FS-fs (loop4): Mounted with checkpoint version = 7ad43cd7 F2FS-fs (loop4): Invalid log sectors per block(393219) log sectorsize(9) F2FS-fs (loop4): Can't find valid F2FS filesystem in 1th superblock mmap: syz-executor.0 (12390) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt.