KCSAN: data-race in __bio_queue_enter / blk_mq_unfreeze_queue

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __bio_queue_enter / blk_mq_unfreeze_queue_nomemrestore block	6				1	151d	151d	0/29	auto-obsoleted due to no activity on 2025/06/01 08:09
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BUG: KCSAN: data-race in __bio_queue_enter / blk_mq_unfreeze_queue_nomemrestore

read-write to 0xffff88810242a1b4 of 4 bytes by task 11980 on cpu 1:
 __blk_mq_unfreeze_queue block/blk-mq.c:217 [inline]
 blk_mq_unfreeze_queue_nomemrestore+0x38/0xc0 block/blk-mq.c:231
 blk_mq_unfreeze_queue include/linux/blk-mq.h:940 [inline]
 loop_set_status+0x3a3/0x6a0 drivers/block/loop.c:1264
 loop_set_status_old drivers/block/loop.c:1360 [inline]
 lo_ioctl+0x71b/0x12b0 drivers/block/loop.c:1549
 blkdev_ioctl+0x34f/0x440 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:584
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:584
 x64_sys_call+0x1816/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810242a1b4 of 4 bytes by task 11976 on cpu 0:
 __bio_queue_enter+0x279/0x5a0 block/blk-core.c:353
 bio_queue_enter block/blk.h:93 [inline]
 blk_mq_submit_bio+0x196/0x1020 block/blk-mq.c:3144
 __submit_bio+0xed/0x4d0 block/blk-core.c:635
 __submit_bio_noacct_mq block/blk-core.c:722 [inline]
 submit_bio_noacct_nocheck+0x208/0x6a0 block/blk-core.c:751
 submit_bio_noacct+0x6ed/0x920 block/blk-core.c:874
 submit_bio+0x2a6/0x2c0 block/blk-core.c:916
 mpage_bio_submit_read fs/mpage.c:75 [inline]
 mpage_readahead+0x295/0x2e0 fs/mpage.c:374
 blkdev_readahead+0x1c/0x30 block/fops.c:496
 read_pages+0xa0/0x480 mm/readahead.c:160
 page_cache_ra_unbounded+0x347/0x380 mm/readahead.c:297
 do_page_cache_ra mm/readahead.c:327 [inline]
 page_cache_ra_order mm/readahead.c:529 [inline]
 page_cache_async_ra+0x4d0/0x4e0 mm/readahead.c:689
 filemap_readahead mm/filemap.c:2572 [inline]
 filemap_get_pages+0x510/0x1150 mm/filemap.c:2617
 filemap_splice_read+0x3a9/0x740 mm/filemap.c:2991
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11976 Comm: syz.1.2606 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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