syzbot

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BUG: KCSAN: data-race in bt_for_each / flush_end_io

write to 0xffff888100e4e420 of 4 bytes by interrupt on cpu 0:
 flush_end_io+0x444/0x780 block/blk-flush.c:249
 __blk_mq_end_request+0x308/0x390 block/blk-mq.c:1047
 blk_mq_end_request+0x3b/0x50 block/blk-mq.c:1059
 lo_complete_rq+0xce/0x180 drivers/block/loop.c:389
 blk_complete_reqs block/blk-mq.c:1132 [inline]
 blk_done_softirq+0x74/0xb0 block/blk-mq.c:1137
 handle_softirqs+0xc3/0x280 kernel/softirq.c:554
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:928
 smpboot_thread_fn+0x31c/0x4c0 kernel/smpboot.c:164
 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

read to 0xffff888100e4e420 of 4 bytes by task 25 on cpu 1:
 blk_mq_find_and_get_req block/blk-mq-tag.c:260 [inline]
 bt_iter block/blk-mq-tag.c:287 [inline]
 __sbitmap_for_each_set include/linux/sbitmap.h:281 [inline]
 sbitmap_for_each_set include/linux/sbitmap.h:302 [inline]
 bt_for_each+0x291/0x480 block/blk-mq-tag.c:324
 blk_mq_queue_tag_busy_iter+0x1a4/0x330 block/blk-mq-tag.c:533
 blk_mq_timeout_work+0xc4/0x350 block/blk-mq.c:1644
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3329
 worker_thread+0x526/0x720 kernel/workqueue.c:3409
 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: 0x00000062 -> 0xffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25 Comm: kworker/1:0H Not tainted 6.10.0-rc7-syzkaller-00012-g34afb82a3c67 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: kblockd blk_mq_timeout_work
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