[moderation] [jfs?] stack segment fault in dbUpdatePMap

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fd57572253bc Merge tag 'sched_ext-for-6.18-rc3-fixes' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d58704580000
kernel config: https://syzkaller.appspot.com/x/.config?x=41ad820f608cb833
dashboard link: https://syzkaller.appspot.com/bug?extid=883243ff272ec3560f55
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [jfs-dis...@lists.sourceforge.net linux-...@vger.kernel.org sha...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c72764dfac75/disk-fd575722.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c0f65b3e3b85/vmlinux-fd575722.xz
kernel image: https://storage.googleapis.com/syzbot-assets/53a0e239c3e5/bzImage-fd575722.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+883243...@syzkaller.appspotmail.com

Oops: stack segment: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 121 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__list_add_valid_or_report+0x3e/0x130 lib/list_debug.c:29
Code: 00 00 00 48 89 d3 48 85 d2 0f 84 93 00 00 00 49 89 f6 49 89 ff 49 bd 00 00 00 00 00 fc ff df 4c 8d 63 08 4c 89 e5 48 c1 ed 03 <42> 80 7c 2d 00 00 74 08 4c 89 e7 e8 a2 c9 9d fd 4d 39 34 24 75 71
RSP: 0018:ffffc9000395fa20 EFLAGS: 00010a06
RAX: 0000000000000000 RBX: dead000000000100 RCX: ffff88801df8da00
RDX: dead000000000100 RSI: ffffc90003171650 RDI: ffff888053d7f010
RBP: 1bd5a00000000021 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1dac52f R12: dead000000000108
R13: dffffc0000000000 R14: ffffc90003171650 R15: ffff888053d7f010
FS: 0000000000000000(0000) GS:ffff888126dfc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002780 CR3: 0000000023378000 CR4: 00000000003526f0
Call Trace:
<TASK>
__list_add_valid include/linux/list.h:96 [inline]
__list_add include/linux/list.h:158 [inline]
list_add include/linux/list.h:177 [inline]
dbUpdatePMap+0x7e4/0xeb0 fs/jfs/jfs_dmap.c:577
txAllocPMap+0x57d/0x6b0 fs/jfs/jfs_txnmgr.c:2426
txUpdateMap+0x81e/0x9c0 fs/jfs/jfs_txnmgr.c:2364
txLazyCommit fs/jfs/jfs_txnmgr.c:2665 [inline]
jfs_lazycommit+0x3f1/0xa10 fs/jfs/jfs_txnmgr.c:2734
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid_or_report+0x3e/0x130 lib/list_debug.c:29
Code: 00 00 00 48 89 d3 48 85 d2 0f 84 93 00 00 00 49 89 f6 49 89 ff 49 bd 00 00 00 00 00 fc ff df 4c 8d 63 08 4c 89 e5 48 c1 ed 03 <42> 80 7c 2d 00 00 74 08 4c 89 e7 e8 a2 c9 9d fd 4d 39 34 24 75 71
RSP: 0018:ffffc9000395fa20 EFLAGS: 00010a06
RAX: 0000000000000000 RBX: dead000000000100 RCX: ffff88801df8da00
RDX: dead000000000100 RSI: ffffc90003171650 RDI: ffff888053d7f010
RBP: 1bd5a00000000021 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1dac52f R12: dead000000000108
R13: dffffc0000000000 R14: ffffc90003171650 R15: ffff888053d7f010
FS: 0000000000000000(0000) GS:ffff888126dfc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002780 CR3: 0000000023378000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 48 89 add %cl,-0x77(%rax)
5: d3 48 85 rorl %cl,-0x7b(%rax)
8: d2 0f rorb %cl,(%rdi)
a: 84 93 00 00 00 49 test %dl,0x49000000(%rbx)
10: 89 f6 mov %esi,%esi
12: 49 89 ff mov %rdi,%r15
15: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13
1c: fc ff df
1f: 4c 8d 63 08 lea 0x8(%rbx),%r12
23: 4c 89 e5 mov %r12,%rbp
26: 48 c1 ed 03 shr $0x3,%rbp
* 2a: 42 80 7c 2d 00 00 cmpb $0x0,0x0(%rbp,%r13,1) <-- trapping instruction
30: 74 08 je 0x3a
32: 4c 89 e7 mov %r12,%rdi
35: e8 a2 c9 9d fd call 0xfd9dc9dc
3a: 4d 39 34 24 cmp %r14,(%r12)
3e: 75 71 jne 0xb1


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Sending this report to the next reporting stage.