syzbot

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BUG: KCSAN: data-race in __bio_queue_enter / blk_freeze_queue

read-write to 0xffff888100c61844 of 4 bytes by task 17509 on cpu 1:
 blk_freeze_queue_start block/blk-mq.c:127 [inline]
 blk_freeze_queue+0x37/0xb0 block/blk-mq.c:166
 blk_mq_freeze_queue+0x15/0x20 block/blk-mq.c:176
 __loop_clr_fd+0x89/0x3b0 drivers/block/loop.c:1150
 loop_clr_fd drivers/block/loop.c:1257 [inline]
 lo_ioctl+0xe93/0x12e0 drivers/block/loop.c:1563
 blkdev_ioctl+0x375/0x460 block/ioctl.c:633
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888100c61844 of 4 bytes by task 17506 on cpu 0:
 __bio_queue_enter+0x1e3/0x4f0 block/blk-core.c:358
 bio_queue_enter block/blk.h:70 [inline]
 blk_mq_submit_bio+0x2db/0xd90 block/blk-mq.c:2964
 __submit_bio+0x11c/0x350 block/blk-core.c:599
 __submit_bio_noacct_mq block/blk-core.c:678 [inline]
 submit_bio_noacct_nocheck+0x449/0x5e0 block/blk-core.c:707
 submit_bio_noacct+0x71c/0x8c0 block/blk-core.c:801
 submit_bio+0xb7/0xc0 block/blk-core.c:834
 submit_bio_wait+0x87/0xd0 block/bio.c:1365
 blkdev_issue_flush+0x53/0x80 block/blk-flush.c:474
 blkdev_fsync+0x74/0xa0 block/fops.c:538
 vfs_fsync_range+0x111/0x120 fs/sync.c:188
 generic_write_sync+0xf2/0x120 include/linux/fs.h:2653
 blkdev_write_iter+0x364/0x390 block/fops.c:700
 do_iter_write+0x4ad/0x770 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3c4/0x980 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17506 Comm: syz-executor.2 Not tainted 6.7.0-rc1-syzkaller-00366-geb3479bc23fa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
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