[syzbot] [block?] [bcachefs?] kernel panic: KASAN: panic_on_warn set ...

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3088d26962e8 Merge tag 'x86-urgent-2025-04-18' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17aed470580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a31f7155996562
dashboard link: https://syzkaller.appspot.com/bug?extid=4eb503ec2b8156835f24
compiler: Debian clang version 15.0.6, Debian LLD 15.0.6

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-3088d269.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5ec84510bfc9/vmlinux-3088d269.xz
kernel image: https://storage.googleapis.com/syzbot-assets/af58d0bee0a4/bzImage-3088d269.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4eb503...@syzkaller.appspotmail.com

Kernel panic - not syncing: KASAN: panic_on_warn set ...
CPU: 0 UID: 0 PID: 47 Comm: kworker/u4:3 Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #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
Workqueue: loop0 loop_workfn
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
panic+0x349/0x880 kernel/panic.c:354
check_panic_on_warn+0x86/0xb0 kernel/panic.c:243
end_report+0x77/0x160 mm/kasan/report.c:227
kasan_report+0x154/0x180 mm/kasan/report.c:636
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x28f/0x2a0 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
put_bh include/linux/buffer_head.h:301 [inline]
end_buffer_read_sync+0xc1/0xd0 fs/buffer.c:161
end_bio_bh_io_sync+0xbf/0x120 fs/buffer.c:2748
blk_update_request+0x5e5/0x1160 block/blk-mq.c:983
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1145
lo_rw_aio_do_completion drivers/block/loop.c:317 [inline]
lo_rw_aio_complete drivers/block/loop.c:325 [inline]
lo_rw_aio+0xdfd/0xf80 drivers/block/loop.c:398
do_req_filebacked drivers/block/loop.c:-1 [inline]
loop_handle_cmd drivers/block/loop.c:1866 [inline]
loop_process_work+0x8e3/0x11f0 drivers/block/loop.c:1901
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464


---
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[Kent Overstreet]

I'm not sure which subsystem this is, but it's definitely not bcachefs -
we don't use buffer heads.

[Kent Overstreet]

On Sat, Apr 19, 2025 at 08:23:50AM -0400, Kent Overstreet wrote:
> I'm not sure which subsystem this is, but it's definitely not bcachefs -
> we don't use buffer heads.

I think there's some incorrect deduplication going on with this bug,
some of the reports do not look closely related, I believe they're all
buffer heads related.

#syz set-subsystems: block fs

[syzbot]

unknown command "set-subsystems:"

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject:
Author: kent.ov...@linux.dev

#syz set subsystems: block fs