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BUG: KCSAN: data-race in blk_mq_unfreeze_queue / blk_queue_enter

write to 0xffff888101ea55bc of 4 bytes by task 5611 on cpu 0:
 blk_mq_unfreeze_queue+0x3c/0xc0 block/blk-mq.c:194
 loop_set_status+0x438/0x5a0 drivers/block/loop.c:1566
 lo_ioctl+0x7af/0x1340 drivers/block/loop.c:1686
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1604
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888101ea55bc of 4 bytes by task 5594 on cpu 1:
 blk_queue_enter+0x2b8/0x560 block/blk-core.c:467
 bio_queue_enter block/blk-core.c:482 [inline]
 __submit_bio_noacct_mq block/blk-core.c:1002 [inline]
 submit_bio_noacct+0x6d4/0x7e0 block/blk-core.c:1044
 submit_bio+0x10c/0x190 include/linux/vmstat.h:81
 submit_bh_wbc+0x2f3/0x330 fs/buffer.c:3050
 submit_bh fs/buffer.c:3056 [inline]
 block_read_full_page+0x78c/0x870 fs/buffer.c:2335
 blkdev_readpage+0x18/0x20 fs/block_dev.c:644
 filemap_read_page+0x69/0x200 mm/filemap.c:2326
 filemap_update_page mm/filemap.c:2394 [inline]
 filemap_get_pages mm/filemap.c:2490 [inline]
 filemap_read+0xc52/0x1220 mm/filemap.c:2550
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1671
 call_read_iter include/linux/fs.h:2108 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x565/0x5d0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5594 Comm: systemd-udevd Not tainted 5.14.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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