[syzbot] [block?] WARNING in blk_mq_dispatch_rq_list

Hello,

syzbot found the following issue on:

HEAD commit:    21d6ac051080 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=17fb5e79580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
dashboard link: https://syzkaller.appspot.com/bug?extid=49b69d460fb5134ee1d7
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/88380e2ddcb9/disk-21d6ac05.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5dba5c2896b7/vmlinux-21d6ac05.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52ac739e37e0/Image-21d6ac05.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

------------[ cut here ]------------
WARNING: block/blk-mq.c:2107 at blk_mq_dispatch_rq_list+0x960/0x13a8 block/blk-mq.c:2107, CPU#0: kworker/0:1H/4345
Modules linked in:
CPU: 0 UID: 0 PID: 4345 Comm: kworker/0:1H Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Workqueue: kblockd blk_mq_run_work_fn
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : blk_mq_dispatch_rq_list+0x960/0x13a8 block/blk-mq.c:2107
lr : blk_mq_dispatch_rq_list+0x960/0x13a8 block/blk-mq.c:2107
sp : ffff8000988b77e0
x29: ffff8000988b78c0 x28: 0000000000000000 x27: 0000000000000000
x26: 1fffe0001918f242 x25: ffff0000c8c79248 x24: ffff0000c8a75800
x23: dfff800000000000 x22: ffff0000c8c79210 x21: ffff8000988b7a48
x20: ffff8000988b7a40 x19: ffff0000c8a75948 x18: 00000000ffffffff
x17: ffff80008a7d6000 x16: 0000000000000004 x15: ffff80008a35fda0
x14: ffff80008a5d5e28 x13: 0000000000000002 x12: 0000000000000000
x11: 0000000000000000 x10: ffff700013116f12 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff80008ab02a68 x4 : 0000000000000000 x3 : 0000000000000010
x2 : 0000000000000000 x1 : ffff0000d4098000 x0 : 0000000000000000
Call trace:
 blk_mq_dispatch_rq_list+0x960/0x13a8 block/blk-mq.c:2107 (P)
 __blk_mq_sched_dispatch_requests+0x250/0x10e8 block/blk-mq-sched.c:299
 blk_mq_sched_dispatch_requests+0xa8/0x158 block/blk-mq-sched.c:329
 blk_mq_run_work_fn+0x214/0x2e4 block/blk-mq.c:2532
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
irq event stamp: 5080
hardirqs last  enabled at (5079): [<ffff8000869308a8>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:187 [inline]
hardirqs last  enabled at (5079): [<ffff8000869308a8>] _raw_spin_unlock_irq+0x30/0x80 kernel/locking/spinlock.c:206
hardirqs last disabled at (5080): [<ffff80008690b3d0>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:445
softirqs last  enabled at (0): [<ffff8000802ec674>] copy_process+0x13a4/0x32e8 kernel/fork.c:2238
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: block/blk.h:703 at req_ref_put_and_test block/blk.h:703 [inline], CPU#0: kworker/0:1H/4345
WARNING: block/blk.h:703 at blk_mq_free_request+0x190/0x210 block/blk-mq.c:829, CPU#0: kworker/0:1H/4345
Modules linked in:
CPU: 0 UID: 0 PID: 4345 Comm: kworker/0:1H Tainted: G        W    L      syzkaller #0 PREEMPT 
Tainted: [W]=WARN, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Workqueue: kblockd blk_mq_run_work_fn
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : req_ref_put_and_test block/blk.h:703 [inline]
pc : blk_mq_free_request+0x190/0x210 block/blk-mq.c:829
lr : req_ref_put_and_test block/blk.h:703 [inline]
lr : blk_mq_free_request+0x190/0x210 block/blk-mq.c:829
sp : ffff8000988b7730
x29: ffff8000988b7730 x28: ffff700013116f0c x27: ffff0000c8c79200
x26: ffff0000d4098000 x25: 1fffe0001918f243 x24: 1fffe0001918f260
x23: dfff800000000000 x22: dfff800000000000 x21: ffff0000c8c7929c
x20: 000000000000007f x19: ffff0000c8c79200 x18: 00000000ffffffff
x17: ffff80008a7d6000 x16: 0000000000000004 x15: ffff80008a35fda0
x14: ffff80008a5d5e28 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: ffff60001918f254 x9 : 0000000000000000
x8 : 0000000000000000 x7 : ffff8000817b1a10 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff80008178be24
x2 : 000000000000007f x1 : ffff0000d4098000 x0 : 0000000000000000
Call trace:
 req_ref_put_and_test block/blk.h:703 [inline] (P)
 blk_mq_free_request+0x190/0x210 block/blk-mq.c:829 (P)
 __blk_mq_end_request+0x32c/0x434 block/blk-mq.c:-1
 blk_mq_end_request+0x68/0x8c block/blk-mq.c:1149
 blk_mq_dispatch_rq_list+0x410/0x13a8 block/blk-mq.c:2129
 __blk_mq_sched_dispatch_requests+0x250/0x10e8 block/blk-mq-sched.c:299
 blk_mq_sched_dispatch_requests+0xa8/0x158 block/blk-mq-sched.c:329
 blk_mq_run_work_fn+0x214/0x2e4 block/blk-mq.c:2532
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
irq event stamp: 5256
hardirqs last  enabled at (5255): [<ffff800080557c84>] seqcount_lockdep_reader_access+0x7c/0xf8 include/linux/seqlock.h:75
hardirqs last disabled at (5256): [<ffff80008690b3d0>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:445
softirqs last  enabled at (5248): [<ffff80008030e6e4>] softirq_handle_end kernel/softirq.c:468 [inline]
softirqs last  enabled at (5248): [<ffff80008030e6e4>] handle_softirqs+0xc28/0xd98 kernel/softirq.c:650
softirqs last disabled at (5083): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:656
---[ end trace 0000000000000000 ]---


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