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VFS: Busy inodes after unmount (use-after-free)

Status: upstream: reported C repro on 2025/07/29 23:52
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+07910bd70ef5a5789202@syzkaller.appspotmail.com
First crash: 268d, last: 3h22m
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: VFS: Busy inodes after unmount (use-after-free) (log)
Repro: C syz .config
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2025/09/15 linux-6.6.y (ToT) 60a9e718726f C [report] VFS: Busy inodes after unmount (use-after-free)
2025/07/30 upstream (ToT) 4b290aae788e C [report] VFS: Busy inodes after unmount (use-after-free)
2025/09/15 upstream (ToT) f83ec76bf285 C Didn't crash
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 VFS: Busy inodes after unmount (use-after-free) 2 C 4 1097d 1153d 0/2 auto-obsoleted due to no activity on 2023/08/20 15:35
upstream VFS: Busy inodes after unmount (use-after-free) (2) btrfs 2 C error 277 236d 347d 29/29 fixed on 2025/09/04 16:57
linux-6.1 VFS: Busy inodes after unmount (use-after-free) origin:lts-only 2 C inconclusive 2367 4h28m 1132d 0/3 upstream: reported C repro on 2023/03/18 09:53
android-5-15 VFS: Busy inodes after unmount (use-after-free) origin:downstream 2 C error done 2 1051d 1153d 0/2 auto-obsoleted due to no activity on 2023/09/15 20:27
android-5-10 VFS: Busy inodes after unmount (use-after-free) 2 C done inconclusive 1 1153d 1153d 0/2 auto-obsoleted due to no activity on 2023/06/25 23:02
upstream VFS: Busy inodes after unmount (use-after-free) (3) fs 2 C error 85 175d 205d 29/29 fixed on 2025/11/18 08:45
upstream VFS: Busy inodes after unmount (use-after-free) (4) jfs 2 C error 26 1d04h 119d 0/29 upstream: reported C repro on 2025/12/25 14:06
upstream VFS: Busy inodes after unmount (use-after-free) fs 2 C error 55684 353d 1184d 28/29 fixed on 2025/05/06 15:33
linux-5.15 VFS: Busy inodes after unmount (use-after-free) missing-backport origin:lts-only 2 C error 2628 4d01h 1131d 0/3 upstream: reported C repro on 2023/03/19 11:46
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/12/17 00:08 1h19m fix candidate upstream OK (0) job log
2025/09/08 07:53 1h54m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
ocfs2: Unmounting device (7,0) on (node local)
VFS: Busy inodes after unmount of loop0 (ocfs2)
------------[ cut here ]------------
kernel BUG at fs/super.c:697!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5876 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:generic_shutdown_super+0x2ad/0x2b0 fs/super.c:695
Code: e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 ac 59 f0 ff 49 8b 16 48 81 c3 60 06 00 00 48 c7 c7 e0 ac d7 8a 48 89 de e8 e3 79 8b 08 <0f> 0b 90 66 0f 1f 00 55 41 57 41 56 53 48 89 fb 49 bf 00 00 00 00
RSP: 0018:ffffc900032b7d20 EFLAGS: 00010246
RAX: 000000000000002f RBX: ffff88802952a660 RCX: e88f5e84af155500
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff110052a54f2 R08: ffff8880b8e28c13 R09: 1ffff110171c5182
R10: dffffc0000000000 R11: ffffed10171c5183 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8d6347e0 R15: ffff88802952a790
FS:  00005555724b4500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1edab93000 CR3: 0000000078efc000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 kill_block_super+0x44/0x90 fs/super.c:1660
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff74fd9da57
Code: a2 c7 05 9c fc 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff8c7023c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007ff74fe32048 RCX: 00007ff74fd9da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff8c702480
RBP: 00007fff8c702480 R08: 00007fff8c703480 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8c703510
R13: 00007ff74fe32048 R14: 000000000001b167 R15: 00007fff8c703550
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_shutdown_super+0x2ad/0x2b0 fs/super.c:695
Code: e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 ac 59 f0 ff 49 8b 16 48 81 c3 60 06 00 00 48 c7 c7 e0 ac d7 8a 48 89 de e8 e3 79 8b 08 <0f> 0b 90 66 0f 1f 00 55 41 57 41 56 53 48 89 fb 49 bf 00 00 00 00
RSP: 0018:ffffc900032b7d20 EFLAGS: 00010246
RAX: 000000000000002f RBX: ffff88802952a660 RCX: e88f5e84af155500
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff110052a54f2 R08: ffff8880b8e28c13 R09: 1ffff110171c5182
R10: dffffc0000000000 R11: ffffed10171c5183 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8d6347e0 R15: ffff88802952a790
FS:  00005555724b4500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000033a25c0 CR3: 0000000078efc000 CR4: 00000000003506e0

Crashes (306):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/29 02:54 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/12/17 01:31 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/12/03 14:42 linux-6.6.y 4791134e4aeb d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/10/29 12:29 linux-6.6.y 4a243110dc88 fd2207e7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/08/02 11:32 linux-6.6.y 3a8ababb8b6a 7368264b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/07/30 11:21 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/24 03:23 linux-6.6.y 9760bf04666d 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/24 03:23 linux-6.6.y 9760bf04666d 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/23 14:18 linux-6.6.y 9760bf04666d 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/23 01:40 linux-6.6.y 9760bf04666d b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/22 13:23 linux-6.6.y 9760bf04666d 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/21 20:09 linux-6.6.y 9760bf04666d 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/21 20:09 linux-6.6.y 9760bf04666d 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/21 08:14 linux-6.6.y 9760bf04666d 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/20 19:16 linux-6.6.y 9760bf04666d e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/18 13:50 linux-6.6.y 9760bf04666d 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/18 06:35 linux-6.6.y 8cee53b8eaeb 5be7a9de .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/18 06:33 linux-6.6.y 8cee53b8eaeb 5be7a9de .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/17 20:04 linux-6.6.y 8cee53b8eaeb 24ecfc1e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/17 03:26 linux-6.6.y 8cee53b8eaeb de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/16 21:47 linux-6.6.y 8cee53b8eaeb 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/16 21:40 linux-6.6.y 8cee53b8eaeb 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/16 03:51 linux-6.6.y 8cee53b8eaeb df15c5f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/15 16:19 linux-6.6.y 8cee53b8eaeb c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/15 05:57 linux-6.6.y 8cee53b8eaeb e2e976a8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/14 16:03 linux-6.6.y 8cee53b8eaeb 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/14 15:54 linux-6.6.y 8cee53b8eaeb 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/14 08:21 linux-6.6.y 8cee53b8eaeb 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/14 03:18 linux-6.6.y 8cee53b8eaeb 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/13 15:49 linux-6.6.y 8cee53b8eaeb 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/13 08:48 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/13 03:56 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/12 10:27 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/12 02:13 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/11 20:18 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/09 06:03 linux-6.6.y 80de0a958133 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/08 19:16 linux-6.6.y 80de0a958133 d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/08 03:55 linux-6.6.y 80de0a958133 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/08 03:54 linux-6.6.y 80de0a958133 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/07 15:52 linux-6.6.y 80de0a958133 628666c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/06 13:46 linux-6.6.y 80de0a958133 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/06 05:33 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/06 04:20 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/06 02:17 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/05 12:35 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/03 02:40 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/03 02:37 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2026/04/02 13:58 linux-6.6.y c09fbcd31ae6 91bc79b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
2025/07/29 23:52 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan VFS: Busy inodes after unmount (use-after-free)
* Struck through repros no longer work on HEAD.