syzbot


possible deadlock in vfs_rename (2)

Status: upstream: reported C repro on 2024/12/31 00:31
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+e7f6162c3a4c0b0f3133@syzkaller.appspotmail.com
First crash: 172d, last: 7d15h
Bug presence (2)
Date Name Commit Repro Result
2025/06/17 linux-6.1.y (ToT) 58485ff1a74f C [report] possible deadlock in delete_one_xattr
2025/06/17 upstream (ToT) 9afe652958c3 C Didn't crash
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in vfs_rename 13 96d 409d 0/3 upstream: reported on 2024/05/08 00:59
upstream possible deadlock in vfs_rename kernel 1 864d 864d 0/29 closed as invalid on 2023/02/08 16:28
linux-6.1 possible deadlock in vfs_rename 8 277d 312d 0/3 auto-obsoleted due to no activity on 2024/12/25 19:29
upstream possible deadlock in vfs_rename (2) ntfs3 3 154d 203d 0/29 auto-obsoleted due to no activity on 2025/04/27 15:12

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.1.141-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor309/4343 is trying to acquire lock:
ffff0000e5c6f380 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff0000e5c6f380 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: vfs_rename+0x670/0xdcc fs/namei.c:4839

but task is already holding lock:
ffff0000e5c77380 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
ffff0000e5c77380 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: vfs_rename+0x60c/0xdcc fs/namei.c:4837

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}:
       down_write_nested+0x64/0x94 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:793 [inline]
       xattr_rmdir fs/reiserfs/xattr.c:106 [inline]
       delete_one_xattr+0xe8/0x2c8 fs/reiserfs/xattr.c:338
       reiserfs_for_each_xattr+0x568/0x68c fs/reiserfs/xattr.c:311
       reiserfs_delete_xattrs+0x2c/0xa4 fs/reiserfs/xattr.c:364
       reiserfs_evict_inode+0x1d8/0x3e8 fs/reiserfs/inode.c:53
       evict+0x3c8/0x810 fs/inode.c:705
       iput_final fs/inode.c:1834 [inline]
       iput+0x764/0x7f4 fs/inode.c:1860
       dentry_unlink_inode+0x360/0x438 fs/dcache.c:405
       __dentry_kill+0x320/0x598 fs/dcache.c:611
       dentry_kill+0xc8/0x248 fs/dcache.c:-1
       dput+0x238/0x454 fs/dcache.c:918
       cleanup_mnt+0x360/0x404 fs/namespace.c:1181
       __cleanup_mnt+0x20/0x30 fs/namespace.c:1189
       task_work_run+0x1ec/0x270 kernel/task_work.c:203
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       do_notify_resume+0x1f70/0x2b0c arch/arm64/kernel/signal.c:1137
       prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
       exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
       el0_svc+0x98/0x138 arch/arm64/kernel/entry-common.c:638
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}:
       down_write_nested+0x64/0x94 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:793 [inline]
       open_xa_root fs/reiserfs/xattr.c:127 [inline]
       open_xa_dir+0x118/0x5d4 fs/reiserfs/xattr.c:152
       xattr_lookup+0x3c/0x268 fs/reiserfs/xattr.c:395
       reiserfs_xattr_set_handle+0xd8/0xd94 fs/reiserfs/xattr.c:533
       reiserfs_xattr_set+0x388/0x4a8 fs/reiserfs/xattr.c:633
       trusted_set+0x98/0xec fs/reiserfs/xattr_trusted.c:31
       __vfs_setxattr+0x388/0x3a4 fs/xattr.c:182
       __vfs_setxattr_noperm+0x120/0x564 fs/xattr.c:216
       __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:277
       vfs_setxattr+0x158/0x2ac fs/xattr.c:309
       ovl_do_setxattr fs/overlayfs/overlayfs.h:252 [inline]
       ovl_setxattr fs/overlayfs/overlayfs.h:264 [inline]
       ovl_make_workdir fs/overlayfs/super.c:1435 [inline]
       ovl_get_workdir+0x950/0x1068 fs/overlayfs/super.c:1539
       ovl_fill_super+0x139c/0x2294 fs/overlayfs/super.c:2095
       mount_nodev+0x68/0x104 fs/super.c:1489
       ovl_mount+0x3c/0x50 fs/overlayfs/super.c:2186
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:632
       vfs_get_tree+0x90/0x274 fs/super.c:1573
       do_new_mount+0x228/0x810 fs/namespace.c:3054
       path_mount+0x5b4/0xe78 fs/namespace.c:3384
       do_mount fs/namespace.c:3397 [inline]
       __do_sys_mount fs/namespace.c:3605 [inline]
       __se_sys_mount fs/namespace.c:3582 [inline]
       __arm64_sys_mount+0x49c/0x584 fs/namespace.c:3582
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&type->i_mutex_dir_key#6){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049
       lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662
       down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       vfs_rename+0x670/0xdcc fs/namei.c:4839
       do_renameat2+0x738/0xa54 fs/namei.c:5027
       __do_sys_renameat2 fs/namei.c:5060 [inline]
       __se_sys_renameat2 fs/namei.c:5057 [inline]
       __arm64_sys_renameat2+0xe0/0xfc fs/namei.c:5057
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6 --> &type->i_mutex_dir_key#6/3 --> &type->i_mutex_dir_key#6/2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->i_mutex_dir_key#6/2);
                               lock(&type->i_mutex_dir_key#6/3);
                               lock(&type->i_mutex_dir_key#6/2);
  lock(&type->i_mutex_dir_key#6);

 *** DEADLOCK ***

5 locks held by syz-executor309/4343:
 #0: ffff0000dae82460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff0000dae82748 (&type->s_vfs_rename_key){+.+.}-{3:3}, at: lock_rename fs/namei.c:3038 [inline]
 #1: ffff0000dae82748 (&type->s_vfs_rename_key){+.+.}-{3:3}, at: do_renameat2+0x2fc/0xa54 fs/namei.c:4966
 #2: ffff0000e5c6e640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #2: ffff0000e5c6e640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: lock_two_directories fs/namei.c:-1 [inline]
 #2: ffff0000e5c6e640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: lock_rename fs/namei.c:3039 [inline]
 #2: ffff0000e5c6e640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: do_renameat2+0x378/0xa54 fs/namei.c:4966
 #3: ffff0000e5c702e0 (&type->i_mutex_dir_key#6/5){+.+.}-{3:3}, at: lock_rename include/linux/fs.h:-1 [inline]
 #3: ffff0000e5c702e0 (&type->i_mutex_dir_key#6/5){+.+.}-{3:3}, at: do_renameat2+0x3ac/0xa54 fs/namei.c:4966
 #4: ffff0000e5c77380 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #4: ffff0000e5c77380 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: vfs_rename+0x60c/0xdcc fs/namei.c:4837

stack backtrace:
CPU: 0 PID: 4343 Comm: syz-executor309 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048
 check_noncircular+0x240/0x2d4 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x293c/0x6544 kernel/locking/lockdep.c:5049
 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662
 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 vfs_rename+0x670/0xdcc fs/namei.c:4839
 do_renameat2+0x738/0xa54 fs/namei.c:5027
 __do_sys_renameat2 fs/namei.c:5060 [inline]
 __se_sys_renameat2 fs/namei.c:5057 [inline]
 __arm64_sys_renameat2+0xe0/0xfc fs/namei.c:5057
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 7) not found (pos 2)

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/13 22:35 linux-6.1.y 58485ff1a74f 98683f8f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_rename
2025/03/15 15:28 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in vfs_rename
2025/01/09 03:00 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in vfs_rename
2025/06/13 19:36 linux-6.1.y 58485ff1a74f 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_rename
2025/06/11 09:28 linux-6.1.y 58485ff1a74f 5d7e17ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_rename
2024/12/31 00:30 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_rename
* Struck through repros no longer work on HEAD.