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Date:   Mon, 25 Oct 2021 04:16:20 -0700
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Subject: [syzbot] KCSAN: data-race in sbitmap_queue_clear /
 sbitmap_queue_clear (3)
From:   syzbot <syzbot+4f8bfd804b4a1f95b8f6@syzkaller.appspotmail.com>
To:     axboe@kernel.dk, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    2f111a6fd5b5 Merge tag 'ceph-for-5.15-rc7' of git://github..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10dae330b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b2868748300e5cf6
dashboard link: https://syzkaller.appspot.com/bug?extid=4f8bfd804b4a1f95b8f6
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4f8bfd804b4a1f95b8f6@syzkaller.appspotmail.com

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

write to 0xffffe8ffffd145b8 of 4 bytes by interrupt on cpu 1:
 sbitmap_queue_clear+0xca/0xf0 lib/sbitmap.c:606
 blk_mq_put_tag+0x82/0x90
 __blk_mq_free_request+0x114/0x180 block/blk-mq.c:507
 blk_mq_free_request+0x2c8/0x340 block/blk-mq.c:541
 __blk_mq_end_request+0x214/0x230 block/blk-mq.c:565
 blk_mq_end_request+0x37/0x50 block/blk-mq.c:574
 lo_complete_rq+0xca/0x170 drivers/block/loop.c:541
 blk_complete_reqs block/blk-mq.c:584 [inline]
 blk_done_softirq+0x69/0x90 block/blk-mq.c:589
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:920
 smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

write to 0xffffe8ffffd145b8 of 4 bytes by interrupt on cpu 0:
 sbitmap_queue_clear+0xca/0xf0 lib/sbitmap.c:606
 blk_mq_put_tag+0x82/0x90
 __blk_mq_free_request+0x114/0x180 block/blk-mq.c:507
 blk_mq_free_request+0x2c8/0x340 block/blk-mq.c:541
 __blk_mq_end_request+0x214/0x230 block/blk-mq.c:565
 blk_mq_end_request+0x37/0x50 block/blk-mq.c:574
 lo_complete_rq+0xca/0x170 drivers/block/loop.c:541
 blk_complete_reqs block/blk-mq.c:584 [inline]
 blk_done_softirq+0x69/0x90 block/blk-mq.c:589
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:920
 smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

value changed: 0x00000035 -> 0x00000044

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10 Comm: ksoftirqd/0 Not tainted 5.15.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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