[v5.15] WARNING in null_process_zoned_cmd

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0996e0926f6b Linux 5.15.220
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14cfa8f9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=21845b39f8fc6be8
dashboard link: https://syzkaller.appspot.com/bug?extid=d114b2c0269e9623dd7a
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dc4b8d8e9340/disk-0996e092.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d165c7b0f84a/vmlinux-0996e092.xz
kernel image: https://storage.googleapis.com/syzbot-assets/27adabc89e72/bzImage-0996e092.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d114b2...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 150 at drivers/block/null_blk/zoned.c:16 null_zone_no drivers/block/null_blk/zoned.c:16 [inline]
WARNING: CPU: 0 PID: 150 at drivers/block/null_blk/zoned.c:16 null_process_zoned_cmd+0xec0/0x1280 drivers/block/null_blk/zoned.c:690
Modules linked in:
CPU: 0 PID: 150 Comm: kworker/0:1H Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: kblockd blk_mq_run_work_fn
RIP: 0010:null_zone_no drivers/block/null_blk/zoned.c:16 [inline]
RIP: 0010:null_process_zoned_cmd+0xec0/0x1280 drivers/block/null_blk/zoned.c:690
Code: 4c 89 ff e8 d2 66 e2 04 89 e8 48 83 c4 58 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 9c 8e 91 fc 0f 0b e9 61 f6 ff ff e8 90 8e 91 fc <0f> 0b 31 c0 e9 6a f2 ff ff e8 82 8e 91 fc 48 c7 c7 e0 ec b4 8c 4c
RSP: 0018:ffffc9000183f708 EFLAGS: 00010293
RAX: ffffffff84e78110 RBX: 0000000000000000 RCX: ffff88801d4b1dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88801d4b1dc0 R09: 0000000000000007
R10: 000000000000000a R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88802151d800 R14: 0000000000000008 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4bafe2c840 CR3: 0000000063776000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
null_handle_cmd+0x362/0x990 drivers/block/null_blk/main.c:1374
blk_mq_dispatch_rq_list+0xa06/0x1c50 block/blk-mq.c:1387
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:200 [inline]
blk_mq_do_dispatch_sched+0xadf/0xc90 block/blk-mq-sched.c:214
__blk_mq_sched_dispatch_requests+0x32c/0x410 block/blk-mq-sched.c:-1
blk_mq_sched_dispatch_requests+0xf4/0x1b0 block/blk-mq-sched.c:366
__blk_mq_run_hw_queue+0xbb/0x100 block/blk-mq.c:1512
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


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