syzbot


possible deadlock in deactivate_super

Status: upstream: reported C repro on 2025/01/29 18:51
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+0ef649bd6963b601e4aa@syzkaller.appspotmail.com
First crash: 121d, last: 1d03h
Bug presence (2)
Date Name Commit Repro Result
2025/05/30 linux-5.15.y (ToT) 98f47d0e9b8c C [report] possible deadlock in deactivate_super
2025/05/30 upstream (ToT) f66bc387efbe C Didn't crash
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in deactivate_super (2) ocfs2 C inconclusive 8072 20d 117d 0/28 upstream: reported C repro on 2025/02/02 14:09
upstream possible deadlock in deactivate_super ext4 C unreliable 9 1137d 1157d 0/28 closed as dup on 2022/03/30 22:17
linux-6.1 possible deadlock in deactivate_super origin:upstream C 1853 14d 121d 0/3 upstream: reported C repro on 2025/01/29 20:18

Sample crash report:
REISERFS warning: green-16003 errcatch_is_left_mergeable: Invalid item type observed, run fsck ASAP
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.180-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor191/4020 is trying to acquire lock:
ffff0000dadfd090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff0000cd32a0e0 (&type->s_umount_key#43){+.+.}-{3:3}, at: deactivate_super+0x100/0x128 fs/super.c:365

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->s_umount_key#43){+.+.}-{3:3}:
       down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
       __do_sys_quotactl_fd fs/quota/quota.c:996 [inline]
       __se_sys_quotactl_fd fs/quota/quota.c:971 [inline]
       __arm64_sys_quotactl_fd+0x2fc/0x4a4 fs/quota/quota.c:971
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (sb_writers#8){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_write+0xf0/0x3ac include/linux/fs.h:1881
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421
       reiserfs_ioctl+0x188/0x4b8 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&sbi->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
       reiserfs_sync_fs+0xa0/0x150 fs/reiserfs/super.c:76
       sync_filesystem+0xe8/0x218 fs/sync.c:56
       generic_shutdown_super+0x70/0x2f0 fs/super.c:448
       kill_block_super+0x70/0xdc fs/super.c:1427
       reiserfs_kill_sb+0x134/0x14c fs/reiserfs/super.c:570
       deactivate_locked_super+0xb8/0x13c fs/super.c:335
       deactivate_super+0x108/0x128 fs/super.c:366
       cleanup_mnt+0x3c0/0x474 fs/namespace.c:1143
       __cleanup_mnt+0x20/0x30 fs/namespace.c:1150
       task_work_run+0x130/0x1e4 kernel/task_work.c:188
       exit_task_work include/linux/task_work.h:33 [inline]
       do_exit+0x670/0x20bc kernel/exit.c:874
       do_group_exit+0x110/0x268 kernel/exit.c:996
       __do_sys_exit_group kernel/exit.c:1007 [inline]
       __se_sys_exit_group kernel/exit.c:1005 [inline]
       __wake_up_parent+0x0/0x60 kernel/exit.c:1005
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
  &sbi->lock --> sb_writers#8 --> &type->s_umount_key#43

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->s_umount_key#43);
                               lock(sb_writers#8);
                               lock(&type->s_umount_key#43);
  lock(&sbi->lock);

 *** DEADLOCK ***

1 lock held by syz-executor191/4020:
 #0: ffff0000cd32a0e0 (&type->s_umount_key#43){+.+.}-{3:3}, at: deactivate_super+0x100/0x128 fs/super.c:365

stack backtrace:
CPU: 0 PID: 4020 Comm: syz-executor191 Not tainted 5.15.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
 reiserfs_sync_fs+0xa0/0x150 fs/reiserfs/super.c:76
 sync_filesystem+0xe8/0x218 fs/sync.c:56
 generic_shutdown_super+0x70/0x2f0 fs/super.c:448
 kill_block_super+0x70/0xdc fs/super.c:1427
 reiserfs_kill_sb+0x134/0x14c fs/reiserfs/super.c:570
 deactivate_locked_super+0xb8/0x13c fs/super.c:335
 deactivate_super+0x108/0x128 fs/super.c:366
 cleanup_mnt+0x3c0/0x474 fs/namespace.c:1143
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1150
 task_work_run+0x130/0x1e4 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x670/0x20bc kernel/exit.c:874
 do_group_exit+0x110/0x268 kernel/exit.c:996
 __do_sys_exit_group kernel/exit.c:1007 [inline]
 __se_sys_exit_group kernel/exit.c:1005 [inline]
 __wake_up_parent+0x0/0x60 kernel/exit.c:1005
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Crashes (683):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/23 16:41 linux-5.15.y f7347f400572 53a8b9bd .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 possible deadlock in deactivate_super
2025/05/10 05:52 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/05/10 05:42 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/18 09:55 linux-5.15.y f7347f400572 2a20f901 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/17 23:27 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/17 11:24 linux-5.15.y f7347f400572 229db4cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/17 02:41 linux-5.15.y f7347f400572 a95239b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/16 00:05 linux-5.15.y f7347f400572 a95239b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/16 00:05 linux-5.15.y f7347f400572 a95239b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/15 12:01 linux-5.15.y f7347f400572 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/15 08:44 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/14 20:20 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/14 16:45 linux-5.15.y f7347f400572 0bd6db41 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/13 05:04 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/11 22:00 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/11 22:00 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/11 17:07 linux-5.15.y f7347f400572 94486846 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/11 06:13 linux-5.15.y f7347f400572 94486846 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/10 18:21 linux-5.15.y f7347f400572 1ef3ab4d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/10 15:48 linux-5.15.y f7347f400572 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/10 15:44 linux-5.15.y f7347f400572 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/10 00:25 linux-5.15.y 0c935c049b5c 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/09 11:20 linux-5.15.y 0c935c049b5c 47d015b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/09 09:35 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/09 09:33 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/08 10:32 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/08 05:04 linux-5.15.y 0c935c049b5c a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/07 15:09 linux-5.15.y 0c935c049b5c a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/05 20:51 linux-5.15.y 0c935c049b5c 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/05 04:11 linux-5.15.y 0c935c049b5c c53ea9c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/04 11:21 linux-5.15.y 0c935c049b5c 1c4febdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/03 19:54 linux-5.15.y 0c935c049b5c d7ae3a11 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/03 07:02 linux-5.15.y 0c935c049b5c 996a9618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/02 17:10 linux-5.15.y 0c935c049b5c c799dfdd .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/02 07:14 linux-5.15.y 0c935c049b5c c799dfdd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/01 16:07 linux-5.15.y 0c935c049b5c b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/01 16:06 linux-5.15.y 0c935c049b5c b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/01 03:42 linux-5.15.y 0c935c049b5c 36d76a97 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/31 17:31 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/31 08:40 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/30 20:52 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/29 19:06 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/29 06:25 linux-5.15.y 0c935c049b5c cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/29 06:25 linux-5.15.y 0c935c049b5c cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/28 16:38 linux-5.15.y 0c935c049b5c 9a1a9e31 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/03/27 16:31 linux-5.15.y 0c935c049b5c 6c09fb82 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/02/18 20:12 linux-5.15.y c16c81c81336 c37c7249 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/02/07 02:41 linux-5.15.y c16c81c81336 8002dd28 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/02/07 02:22 linux-5.15.y c16c81c81336 8002dd28 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/01/30 11:31 linux-5.15.y 003148680b79 afe4eff5 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan possible deadlock in deactivate_super
2025/04/07 19:13 linux-5.15.y 0c935c049b5c a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in deactivate_super
2025/01/29 21:50 linux-5.15.y 003148680b79 136953f1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 possible deadlock in deactivate_super
2025/01/29 18:50 linux-5.15.y 003148680b79 136953f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in deactivate_super
* Struck through repros no longer work on HEAD.