[moderation] [mm?] [fs?] linux-next test error: kernel panic: kernel: panic_on_warn set ...

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d0630b758e59 Add linux-next specific files for 20250826
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17280462580000
kernel config: https://syzkaller.appspot.com/x/.config?x=667190dc7994a732
dashboard link: https://syzkaller.appspot.com/bug?extid=0aa2e4c63f722956779d
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org linux...@vger.kernel.org s...@canb.auug.org.au wi...@infradead.org]

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f937c7568a44/disk-d0630b75.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ad694e2e886e/vmlinux-d0630b75.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5f0a94108a02/bzImage-d0630b75.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0aa2e4...@syzkaller.appspotmail.com

ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 UID: 0 PID: 1150 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<TASK>
dump_stack_lvl+0x99/0x250 lib/dump_stack.c:120
vpanic+0x281/0x750 kernel/panic.c:435
panic+0xb9/0xc0 kernel/panic.c:571
check_panic_on_warn kernel/panic.c:328 [inline]
__warn+0x334/0x4c0 kernel/panic.c:844
__report_bug lib/bug.c:195 [inline]
report_bug+0x2be/0x4f0 lib/bug.c:215
handle_bug+0x84/0x160 arch/x86/kernel/traps.c:338
exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:392
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:616
RIP: 0010:inode_to_wb include/linux/backing-dev.h:239 [inline]
RIP: 0010:__folio_start_writeback+0x9d5/0xb70 mm/page-writeback.c:3027
Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 2e a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 6c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 5e 04 c6 ff 48 c7 c7 20 fc 5f 8e 4c 89
RSP: 0018:ffffc900040f6ea0 EFLAGS: 00010293
RAX: ffffffff81fadbd4 RBX: ffffea0000930e40 RCX: ffff888026e78000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040f7010 R08: ffffc900040f6f97 R09: 0000000000000000
R10: ffffc900040f6f80 R11: fffff5200081edf3 R12: ffffea0000930e48
R13: 0000000000000000 R14: ffff888148ca6480 R15: ffff888148ca6260
__block_write_full_folio+0x75f/0xe10 fs/buffer.c:1928
blkdev_writepages+0xd1/0x170 block/fops.c:484
do_writepages+0x32b/0x550 mm/page-writeback.c:2604
__writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[Aleksandr Nogikh]

#syz dup: linux-next test error: WARNING in __folio_start_writeback

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