[moderation] [block?] KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f92f4749861b Merge tag 'clk-fixes-for-linus' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11e4bb30580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1fe4854f351e948c
dashboard link: https://syzkaller.appspot.com/bug?extid=f943d131cf3b17fafe7e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ax...@kernel.dk linux...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91075015d2af/disk-f92f4749.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2b54698817e6/vmlinux-f92f4749.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3e887dcf99d5/bzImage-f92f4749.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f943d1...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list

read to 0xffff88810219baf8 of 4 bytes by task 3522 on cpu 1:
blk_mq_update_dispatch_busy block/blk-mq.c:1983 [inline]
blk_mq_dispatch_rq_list+0xd7b/0xfa0 block/blk-mq.c:2204
__blk_mq_sched_dispatch_requests+0x1ce/0xd50 block/blk-mq-sched.c:301
blk_mq_sched_dispatch_requests+0x88/0x120 block/blk-mq-sched.c:331
blk_mq_run_hw_queue+0x18a/0x230 block/blk-mq.c:2354
blk_mq_run_hw_queues+0x1ac/0x240 block/blk-mq.c:2403
blk_mq_requeue_work+0x3fa/0x430 block/blk-mq.c:1568
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
kthread+0x1d1/0x210 kernel/kthread.c:389
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

write to 0xffff88810219baf8 of 4 bytes by task 46 on cpu 0:
blk_mq_dispatch_rq_list+0xd99/0xfa0
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
__blk_mq_sched_dispatch_requests+0x604/0xd50 block/blk-mq-sched.c:309
blk_mq_sched_dispatch_requests+0x88/0x120 block/blk-mq-sched.c:331
blk_mq_run_work_fn+0x65/0xe0 block/blk-mq.c:2530
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
kthread+0x1d1/0x210 kernel/kthread.c:389
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000002 -> 0x00000003

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 46 Comm: kworker/0:1H Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: kblockd blk_mq_run_work_fn
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.