syzbot

BUG: KCSAN: data-race in loop_configure / loop_queue_rq

write to 0xffff88810032e678 of 4 bytes by task 32009 on cpu 0:
 loop_configure+0xb09/0xca0 drivers/block/loop.c:1105
 lo_ioctl+0x682/0x12e0
 blkdev_ioctl+0x375/0x460 block/ioctl.c:621
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810032e678 of 4 bytes by task 4898 on cpu 1:
 loop_queue_rq+0x55/0x650 drivers/block/loop.c:1853
 __blk_mq_issue_directly block/blk-mq.c:2572 [inline]
 blk_mq_try_issue_directly+0x282/0x4d0 block/blk-mq.c:2631
 blk_mq_submit_bio+0xb03/0xd70 block/blk-mq.c:3004
 __submit_bio+0x11c/0x350 block/blk-core.c:598
 __submit_bio_noacct_mq block/blk-core.c:677 [inline]
 submit_bio_noacct_nocheck+0x449/0x5e0 block/blk-core.c:706
 submit_bio_noacct+0x75c/0x900 block/blk-core.c:805
 submit_bio+0xb7/0xc0 block/blk-core.c:838
 submit_bh_wbc+0x270/0x2b0 fs/buffer.c:2840
 submit_bh fs/buffer.c:2845 [inline]
 block_read_full_folio+0x647/0x720 fs/buffer.c:2466
 blkdev_read_folio+0x1c/0x20 block/fops.c:396
 filemap_read_folio mm/filemap.c:2389 [inline]
 filemap_update_page mm/filemap.c:2473 [inline]
 filemap_get_pages+0xc11/0xea0 mm/filemap.c:2587
 filemap_read+0x1fb/0x670 mm/filemap.c:2658
 blkdev_read_iter+0x217/0x2c0 block/fops.c:616
 call_read_iter include/linux/fs.h:1865 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3da/0x5c0 fs/read_write.c:470
 ksys_read+0xeb/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4898 Comm: udevd Not tainted 6.5.0-rc3-syzkaller-00018-g0b5547c51827 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
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