loop4: detected capacity change from 0 to 264192
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BUG: KCSAN: data-race in blk_mq_rq_ctx_init / blk_mq_rq_ctx_init

read to 0xffff888101dc4150 of 8 bytes by task 4498 on cpu 0:
 blk_mq_rq_ctx_init+0x3ca/0x4e0 block/blk-mq.c:351
 __blk_mq_alloc_request+0x270/0x290 block/blk-mq.c:406
 blk_mq_submit_bio+0x27f/0xec0 block/blk-mq.c:2206
 __submit_bio+0x41a/0x480 block/blk-core.c:929
 __submit_bio_noacct_mq block/blk-core.c:1009 [inline]
 submit_bio_noacct+0x46d/0x530 block/blk-core.c:1039
 submit_bio+0x10c/0x190
 mpage_bio_submit fs/mpage.c:66 [inline]
 mpage_readahead+0x23e/0x280 fs/mpage.c:393
 blkdev_readahead+0x18/0x20 block/fops.c:347
 read_pages+0xb6/0x540 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:883 [inline]
 filemap_get_pages mm/filemap.c:2545 [inline]
 filemap_read+0x3ad/0x1220 mm/filemap.c:2628
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2779
 blkdev_read_iter+0xb9/0xf0 block/fops.c:545
 call_read_iter include/linux/fs.h:2157 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x66c/0x750 fs/read_write.c:485
 ksys_read+0xd9/0x190 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+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff888101dc4150 of 8 bytes by task 7657 on cpu 1:
 blk_mq_rq_ctx_init+0x3dc/0x4e0 block/blk-mq.c:351
 __blk_mq_alloc_request+0x270/0x290 block/blk-mq.c:406
 blk_mq_submit_bio+0x27f/0xec0 block/blk-mq.c:2206
 __submit_bio+0x41a/0x480 block/blk-core.c:929
 __submit_bio_noacct_mq block/blk-core.c:1009 [inline]
 submit_bio_noacct+0x46d/0x530 block/blk-core.c:1039
 submit_bio+0x10c/0x190
 submit_bh_wbc+0x2f3/0x330 fs/buffer.c:3054
 submit_bh fs/buffer.c:3060 [inline]
 write_dirty_buffer+0xde/0xf0 fs/buffer.c:3128
 fat_sync_bhs+0x52/0x160 fs/fat/misc.c:361
 fat_zeroed_cluster+0x2b3/0x5e0 fs/fat/dir.c:1108
 fat_alloc_new_dir+0x48d/0x500 fs/fat/dir.c:1185
 vfat_mkdir+0x81/0x230 fs/fat/namei_vfat.c:861
 vfs_mkdir+0x2c3/0x3e0 fs/namei.c:3885
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3911
 __do_sys_mkdirat fs/namei.c:3926 [inline]
 __se_sys_mkdirat fs/namei.c:3924 [inline]
 __x64_sys_mkdirat+0x4c/0x60 fs/namei.c:3924
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000000007ef -> 0x00000000000007f0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7657 Comm: syz-executor.4 Not tainted 5.15.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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