[v5.15] kernel panic: kernel: panic_on_warn set ...

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11c95992580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e6ed99963d6ee1d
dashboard link: https://syzkaller.appspot.com/bug?extid=59627038480defd97d65
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/900f9b9bd850/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e089a5019a6/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b319f477b907/bzImage-68efe5a6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+596270...@syzkaller.appspotmail.com

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:00007ffc18afef08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fb7f6713d7d RCX: 00007fb7f6690a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc18afefc0
RBP: 00007ffc18afefc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc18b00050
R13: 00007fb7f6713d7d R14: 000000000000edeb R15: 00007ffc18b00090
</TASK>
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 PID: 4184 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
panic+0x2c9/0x7f0 kernel/panic.c:309
check_panic_on_warn kernel/panic.c:229 [inline]
__warn+0x248/0x2b0 kernel/panic.c:680
report_bug+0x1b7/0x2e0 lib/bug.c:199
handle_bug+0x3a/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:inode_to_wb include/linux/backing-dev.h:285 [inline]
RIP: 0010:account_page_dirtied mm/page-writeback.c:2474 [inline]
RIP: 0010:__set_page_dirty+0xaf5/0xdc0 mm/page-writeback.c:2522
Code: 4f d8 ff 49 ff cf e9 5b fc ff ff e8 e5 4f d8 ff 48 ff cb e9 e4 fb ff ff e8 d8 4f d8 ff 48 ff cb e9 c4 fc ff ff e8 cb 4f d8 ff <0f> 0b 43 80 3c 3e 00 0f 85 8f f9 ff ff e9 92 f9 ff ff 89 d9 80 e1
RSP: 0018:ffffc90002f1fad8 EFLAGS: 00010093
RAX: ffffffff819f7c45 RBX: 0000000000000000 RCX: ffff8880738f3b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffea0000a70380 R08: dffffc0000000000 R09: ffffed100399e9d7
R10: ffffed100399e9d7 R11: 1ffff1100399e9d6 R12: ffff88801ccf4d38
R13: ffff88801ccf4eb0 R14: 1ffff1100399e9d6 R15: dffffc0000000000
mark_buffer_dirty+0x2d7/0x490 fs/buffer.c:1108
gfs2_unpin+0x126/0x9a0 fs/gfs2/lops.c:111
buf_lo_after_commit+0x15a/0x1a0 fs/gfs2/lops.c:750
lops_after_commit fs/gfs2/lops.h:49 [inline]
gfs2_log_flush+0x1145/0x2610 fs/gfs2/log.c:1108
gfs2_kill_sb+0x50/0xd0 fs/gfs2/ops_fstype.c:1734
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x418/0x4d0 fs/namespace.c:1148
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb7f6690a77
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:00007ffc18afef08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fb7f6713d7d RCX: 00007fb7f6690a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc18afefc0
RBP: 00007ffc18afefc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc18b00050
R13: 00007fb7f6713d7d R14: 000000000000edeb R15: 00007ffc18b00090
</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..
----------------
Code disassembly (best guess), 3 bytes skipped:
0: ff f7 push %rdi
2: d8 64 89 01 fsubs 0x1(%rcx,%rcx,4)
6: 48 83 c8 ff or $0xffffffffffffffff,%rax
a: c3 ret
b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
10: 31 f6 xor %esi,%esi
12: e9 09 00 00 00 jmp 0x20
17: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
1e: 00 00
20: b8 a6 00 00 00 mov $0xa6,%eax
25: 0f 05 syscall
* 27: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax <-- trapping instruction
2d: 77 01 ja 0x30
2f: c3 ret
30: 48 c7 c2 a8 ff ff ff mov $0xffffffffffffffa8,%rdx
37: f7 d8 neg %eax
39: 64 89 02 mov %eax,%fs:(%rdx)
3c: b8 .byte 0xb8


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