syzbot
WARNING in blk_mq_dispatch_rq_list
Status:
upstream: reported on 2026/08/22 00:10
Subsystems:
block
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+49b69d460fb5134ee1d7@syzkaller.appspotmail.com
First crash: 19d, last: 1d10h
Sample crash report:
------------[ 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/4381
Modules linked in:
CPU: 0 UID: 0 PID: 4381 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 : ffff8000967e7800
x29: ffff8000967e78e0 x28: 0000000000000000 x27: ffff0000c818a080
x26: 1fffe00019065182 x25: ffff0000c8328c48 x24: ffff0000c818a000
x23: dfff800000000000 x22: ffff0000c8328c10 x21: ffff8000967e7a68
x20: ffff8000967e7a60 x19: ffff0000c818a148 x18: 00000000ffffffff
x17: 0000000000000003 x16: ffff800088bf7000 x15: ffff800088ca7ee0
x14: ffff80008b0df2b0 x13: 0000000000000002 x12: 0000000000000000
x11: 0000000000000000 x10: ffff700012cfcf16 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff80008ac029f0 x4 : 0000000000000000 x3 : 0000000000000010
x2 : 0000000000000000 x1 : ffff0000c6f09d80 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:3387 [inline]
process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3470
worker_thread+0x798/0xbd0 kernel/workqueue.c:3551
kthread+0x304/0x3d4 kernel/kthread.c:436
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
irq event stamp: 6142
hardirqs last enabled at (6141): [<ffff8000869a99e0>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:219 [inline]
hardirqs last enabled at (6141): [<ffff8000869a99e0>] _raw_spin_unlock_irq+0x30/0x80 kernel/locking/spinlock.c:229
hardirqs last disabled at (6142): [<ffff8000869841d4>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:445
softirqs last enabled at (4546): [<ffff800080311114>] softirq_handle_end kernel/softirq.c:491 [inline]
softirqs last enabled at (4546): [<ffff800080311114>] handle_softirqs+0xc28/0xd98 kernel/softirq.c:673
softirqs last disabled at (4525): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:679
---[ 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/4381
WARNING: block/blk.h:703 at blk_mq_free_request+0x190/0x210 block/blk-mq.c:829, CPU#0: kworker/0:1H/4381
Modules linked in:
CPU: 0 UID: 0 PID: 4381 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 : ffff8000967e7750
x29: ffff8000967e7750 x28: ffff700012cfcf10 x27: ffff0000c8328c00
x26: ffff0000c6f09d80 x25: 1fffe00019065183 x24: 1fffe000190651a0
x23: dfff800000000000 x22: dfff800000000000 x21: ffff0000c8328c9c
x20: 000000000000007f x19: ffff0000c8328c00 x18: 00000000ffffffff
x17: 0000000000000003 x16: ffff800088bf7000 x15: ffff800088ca7ee0
x14: ffff80008b0df2b0 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: ffff600019065194 x9 : 0000000000000000
x8 : 0000000000000000 x7 : ffff800081808d28 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000817e3144
x2 : 000000000000007f x1 : ffff0000c6f09d80 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:3387 [inline]
process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3470
worker_thread+0x798/0xbd0 kernel/workqueue.c:3551
kthread+0x304/0x3d4 kernel/kthread.c:436
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
irq event stamp: 6350
hardirqs last enabled at (6349): [<ffff80008055b5c8>] seqcount_lockdep_reader_access+0x7c/0xf8 include/linux/seqlock.h:75
hardirqs last disabled at (6350): [<ffff8000869841d4>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:445
softirqs last enabled at (6342): [<ffff800080311114>] softirq_handle_end kernel/softirq.c:491 [inline]
softirqs last enabled at (6342): [<ffff800080311114>] handle_softirqs+0xc28/0xd98 kernel/softirq.c:673
softirqs last disabled at (6145): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:679
---[ end trace 0000000000000000 ]---
* Struck through repros no longer work on HEAD.