[moderation] [fs?] BUG: corrupted list in do_lock_mount

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2ccec5944606 Merge tag 'erofs-for-6.18-rc6-fixes' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170f4212580000
kernel config: https://syzkaller.appspot.com/x/.config?x=929790bc044e87d7
dashboard link: https://syzkaller.appspot.com/bug?extid=8d78424503d7fa54e69e
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-2ccec594.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7df9a591c737/vmlinux-2ccec594.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5dedfa8cb69b/bzImage-2ccec594.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d7842...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz"
gfs2: fsid=syz:syz: Now mounting FS (format 1801)...
gfs2: fsid=syz:syz.0: journal 0 mapped with 1 extents in 0ms
gfs2: fsid=syz:syz.0: first mount done, others may mount
slab gfs2_inode start ffff888043304f80 pointer offset 304 size 1568
list_del corruption. prev->next should be ffffc9000d42fb60, but was ffff8880433050b0. (prev=ffff8880433050b0)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 7b 25 71 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 7c f6 92 fd 49 8b 17 48 c7 c7 80 1d bf 8b 48 89 de 4c 89 f9 e8 77 29 93 fc 90 <0f> 0b 4c 89 f7 e8 4c 25 71 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4d
RSP: 0018:ffffc9000d42f9f0 EFLAGS: 00010046
RAX: 000000000000006d RBX: ffffc9000d42fb60 RCX: 3f4f2a7e59e0d100
RDX: 0000000000000000 RSI: 0000000080000002 RDI: 0000000000000000
RBP: ffffc9000d42fc30 R08: ffff88801fe24293 R09: 1ffff11003fc4852
R10: dffffc0000000000 R11: ffffed1003fc4853 R12: 1ffff11008660a16
R13: dffffc0000000000 R14: ffff8880433050b0 R15: ffff8880433050b0
FS: 00007fc2cc5426c0(0000) GS:ffff88808d730000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffea21adec0 CR3: 0000000042383000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__list_del_entry_valid include/linux/list.h:132 [inline]
__list_del_entry include/linux/list.h:223 [inline]
list_del include/linux/list.h:237 [inline]
rwsem_try_write_lock kernel/locking/rwsem.c:662 [inline]
rwsem_down_write_slowpath+0x91e/0xfe0 kernel/locking/rwsem.c:1159
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
inode_lock include/linux/fs.h:980 [inline]
do_lock_mount+0x29f/0x930 fs/namespace.c:2749
__do_sys_pivot_root fs/namespace.c:4578 [inline]
__se_sys_pivot_root+0x305/0xbf0 fs/namespace.c:4550
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc2cb78f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc2cc542038 EFLAGS: 00000246 ORIG_RAX: 000000000000009b
RAX: ffffffffffffffda RBX: 00007fc2cb9e6180 RCX: 00007fc2cb78f6c9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000200000000100
RBP: 00007fc2cb811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc2cb9e6218 R14: 00007fc2cb9e6180 R15: 00007ffea21aea68
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 7b 25 71 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 7c f6 92 fd 49 8b 17 48 c7 c7 80 1d bf 8b 48 89 de 4c 89 f9 e8 77 29 93 fc 90 <0f> 0b 4c 89 f7 e8 4c 25 71 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4d
RSP: 0018:ffffc9000d42f9f0 EFLAGS: 00010046
RAX: 000000000000006d RBX: ffffc9000d42fb60 RCX: 3f4f2a7e59e0d100
RDX: 0000000000000000 RSI: 0000000080000002 RDI: 0000000000000000
RBP: ffffc9000d42fc30 R08: ffff88801fe24293 R09: 1ffff11003fc4852
R10: dffffc0000000000 R11: ffffed1003fc4853 R12: 1ffff11008660a16
R13: dffffc0000000000 R14: ffff8880433050b0 R15: ffff8880433050b0
FS: 00007fc2cc5426c0(0000) GS:ffff88808d730000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffea21adec0 CR3: 0000000042383000 CR4: 0000000000352ef0


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