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BUG: KCSAN: data-race in blk_mq_unfreeze_queue / blk_queue_enter

write to 0xffff8881012265f4 of 4 bytes by task 17036 on cpu 1:
 blk_mq_unfreeze_queue+0x3c/0xc0 block/blk-mq.c:194
 loop_set_status+0x43e/0x5a0 drivers/block/loop.c:1564
 lo_ioctl+0x7af/0x1370 drivers/block/loop.c:1684
 blkdev_ioctl+0x1d0/0x3e0 block/ioctl.c:589
 block_ioctl+0x6d/0x80 fs/block_dev.c:1421
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 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 0xffff8881012265f4 of 4 bytes by task 16876 on cpu 0:
 blk_queue_enter+0x2b8/0x560 block/blk-core.c:462
 bio_queue_enter block/blk-core.c:477 [inline]
 __submit_bio_noacct_mq block/blk-core.c:989 [inline]
 submit_bio_noacct+0x6d4/0x7e0 block/blk-core.c:1031
 submit_bio+0x10c/0x190 include/linux/vmstat.h:81
 mpage_bio_submit fs/mpage.c:66 [inline]
 mpage_readahead+0x23e/0x280 fs/mpage.c:393
 blkdev_readahead+0x18/0x20 fs/block_dev.c:652
 read_pages+0xa5/0x530 mm/readahead.c:130
 page_cache_ra_unbounded+0x3d2/0x430 mm/readahead.c:239
 do_page_cache_ra mm/readahead.c:269 [inline]
 force_page_cache_ra+0x256/0x290 mm/readahead.c:301
 page_cache_sync_ra+0xcc/0xe0 mm/readahead.c:575
 page_cache_sync_readahead include/linux/pagemap.h:884 [inline]
 filemap_get_pages mm/filemap.c:2548 [inline]
 filemap_read+0x39d/0x1210 mm/filemap.c:2631
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2782
 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1488
 call_read_iter include/linux/fs.h:2157 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x651/0x730 fs/read_write.c:485
 ksys_read+0xce/0x180 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:631
 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: 0 PID: 16876 Comm: systemd-udevd Tainted: G        W         5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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