[syzbot] [jfs?] VFS: Busy inodes after unmount (use-after-free) (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ccd1cdca5cd4 Merge tag 'nfsd-6.19-1' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1697109a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18
dashboard link: https://syzkaller.appspot.com/bug?extid=d569e274f46ca86f78fa
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b1c8fc580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1478e022580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f7b489f9e06c/disk-ccd1cdca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6a3b40a08a43/vmlinux-ccd1cdca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/deb72d1923f7/bzImage-ccd1cdca.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/6c19056fd03d/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16972f1a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d569e2...@syzkaller.appspotmail.com

tblock:ffffc900027792a0: 00000002 00000000 027793b8 ffffc900
tblock:ffffc900027792b0: 99a20540 ffffffff 00003ab0 00000000
tblock:ffffc900027792c0: 44b53100 ffff8881 00000003 00000ab0
tblock:ffffc900027792d0: 00000000 dead4ead ffffffff 00000000
tblock:ffffc900027792e0: ffffffff ffffffff 99a203c0 ffffffff
tblock:ffffc900027792f0: 00000000 00000000 00000000 00000000
tblock:ffffc90002779300: 8ba58f60 ffffffff 00000300 00000000
tblock:ffffc90002779310: 02779310 ffffc900 02779310 ffffc900
tblock:ffffc90002779320: 5a664d70 ffff8880 00000000 00000000
VFS: Busy inodes after unmount of loop0 (jfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:653!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5960 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:generic_shutdown_super+0x2bc/0x2c0 fs/super.c:651
Code: 03 42 80 3c 28 00 74 08 4c 89 f7 e8 8e fa ed ff 49 8b 16 48 81 c3 68 06 00 00 48 c7 c7 e0 b2 79 8b 48 89 de e8 a5 8c ee fe 90 <0f> 0b 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f
RSP: 0018:ffffc9000404fd00 EFLAGS: 00010246
RAX: 000000000000002d RBX: ffff8880318d6668 RCX: 29d16eab6a395c00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff1100631acf0 R08: ffff8880b86247d3 R09: 1ffff110170c48fa
R10: dffffc0000000000 R11: ffffed10170c48fb R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8e38bea0 R15: ffff8880318d6780
FS: 00005555777b6500(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbab6082000 CR3: 0000000030db6000 CR4: 0000000000350ef0
Call Trace:
<TASK>
kill_block_super+0x44/0x90 fs/super.c:1722
deactivate_locked_super+0xbc/0x130 fs/super.c:474
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
task_work_run+0x1d4/0x260 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb469390a77
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 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 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc903b6258 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007fb469390a77
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffc903b7400
RBP: 00007fb469413d7d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffc903b7400
R13: 00007fb469413d7d R14: 00005555777b64a8 R15: 00007ffc903b84d0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_shutdown_super+0x2bc/0x2c0 fs/super.c:651
Code: 03 42 80 3c 28 00 74 08 4c 89 f7 e8 8e fa ed ff 49 8b 16 48 81 c3 68 06 00 00 48 c7 c7 e0 b2 79 8b 48 89 de e8 a5 8c ee fe 90 <0f> 0b 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f
RSP: 0018:ffffc9000404fd00 EFLAGS: 00010246
RAX: 000000000000002d RBX: ffff8880318d6668 RCX: 29d16eab6a395c00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff1100631acf0 R08: ffff8880b86247d3 R09: 1ffff110170c48fa
R10: dffffc0000000000 R11: ffffed10170c48fb R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8e38bea0 R15: ffff8880318d6780
FS: 00005555777b6500(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005619d76b3a38 CR3: 0000000030db6000 CR4: 0000000000350ef0


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