[moderation] [block?] KCSAN: data-race in blk_mq_put_driver_tag / blk_mq_tagset_busy_iter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6b4b543fa187 Merge tag 'parisc-for-7.4-rc1' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1715553e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e8da0c22f867139b
dashboard link: https://syzkaller.appspot.com/bug?extid=106207df4f48565a7c02
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
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/0e18b98d7c7b/disk-6b4b543f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/409ff1890477/vmlinux-6b4b543f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/012382667008/bzImage-6b4b543f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+106207...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in blk_mq_put_driver_tag / blk_mq_tagset_busy_iter

write to 0xffff8881035f5e60 of 4 bytes by task 9669 on cpu 0:
__blk_mq_put_driver_tag block/blk-mq.h:361 [inline]
blk_mq_put_driver_tag+0x121/0x140 block/blk-mq.h:369
__blk_mq_requeue_request+0x23/0x180 block/blk-mq.c:1521
blk_mq_handle_dev_resource block/blk-mq.c:2019 [inline]
blk_mq_dispatch_rq_list+0x749/0xef0 block/blk-mq.c:2140
__blk_mq_sched_dispatch_requests+0x1db/0xce0 block/blk-mq-sched.c:299
blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x145/0x1e0 block/blk-mq.c:2370
blk_mq_dispatch_list+0x838/0x9f0 arch/x86/include/asm/bitops.h:-1
blk_mq_flush_plug_list+0x2cd/0x320 block/blk-mq.c:2980
blk_add_rq_to_plug+0xf0/0x3f0 block/blk-mq.c:1399
blk_mq_submit_bio+0xd16/0x1210 block/blk-mq.c:3210
__submit_bio+0x54/0x3d0 block/blk-core.c:674
__submit_bio_noacct_mq block/blk-core.c:757 [inline]
submit_bio_noacct_nocheck+0x1c6/0x620 block/blk-core.c:791
submit_bio_noacct+0x738/0x970 block/blk-core.c:929
submit_bio+0x2a4/0x2c0 block/blk-core.c:970
bio_chain_and_submit+0x84/0xb0 block/bio.c:396
__blkdev_issue_zero_pages+0x1f7/0x240 block/blk-lib.c:215
blkdev_issue_zero_pages block/blk-lib.c:231 [inline]
blkdev_issue_zeroout+0x39c/0x4e0 block/blk-lib.c:312
blk_ioctl_zeroout block/ioctl.c:244 [inline]
blkdev_common_ioctl+0x1a07/0x2060 block/ioctl.c:667
blkdev_ioctl+0x31f/0x460 block/ioctl.c:792
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x239d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881035f5e60 of 4 bytes by task 426 on cpu 1:
blk_mq_find_and_get_req block/blk-mq-tag.c:274 [inline]
bt_tags_iter block/blk-mq-tag.c:369 [inline]
__sbitmap_for_each_set include/linux/sbitmap.h:269 [inline]
sbitmap_for_each_set include/linux/sbitmap.h:290 [inline]
bt_tags_for_each block/blk-mq-tag.c:404 [inline]
__blk_mq_all_tag_iter block/blk-mq-tag.c:415 [inline]
blk_mq_tagset_busy_iter+0x643/0x860 block/blk-mq-tag.c:459
scsi_host_busy+0x4e/0x80 drivers/scsi/hosts.c:631
scsi_host_queue_ready drivers/scsi/scsi_lib.c:1502 [inline]
scsi_queue_rq+0x4e0/0x19f0 drivers/scsi/scsi_lib.c:1900
blk_mq_dispatch_rq_list+0x5d2/0xef0 block/blk-mq.c:2131
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0x86c/0xce0 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x145/0x1e0 block/blk-mq.c:2370
blk_mq_run_hw_queues+0x18e/0x270 block/blk-mq.c:2418
blk_mq_requeue_work+0x3ca/0x400 block/blk-mq.c:1585
process_one_work kernel/workqueue.c:3495 [inline]
process_scheduled_works+0x53f/0xa20 kernel/workqueue.c:3578
worker_thread+0x56c/0x770 kernel/workqueue.c:3659
kthread+0x223/0x270 kernel/kthread.c:436
ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x000023d9 -> 0xffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 426 Comm: kworker/1:1H Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: kblockd blk_mq_requeue_work
==================================================================


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