================================================================== BUG: KCSAN: data-race in blk_mq_rq_ctx_init / blk_mq_rq_ctx_init read to 0xffff888101c9d150 of 8 bytes by task 21302 on cpu 1: 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 submit_bh_wbc+0x2f3/0x330 fs/buffer.c:3054 submit_bh+0x21/0x30 fs/buffer.c:3060 __ext4_read_bh fs/ext4/super.c:155 [inline] ext4_read_bh+0xf1/0x170 fs/ext4/super.c:179 ext4_read_bh_lock fs/ext4/super.c:191 [inline] __ext4_sb_bread_gfp fs/ext4/super.c:223 [inline] ext4_sb_bread_unmovable+0xf7/0x1a0 fs/ext4/super.c:240 ext4_fill_super+0x22c4/0x7830 fs/ext4/super.c:4336 mount_bdev+0x1e8/0x290 fs/super.c:1368 ext4_mount+0x2d/0x40 fs/ext4/super.c:6515 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498 do_new_mount fs/namespace.c:2988 [inline] path_mount+0x11ec/0x1d20 fs/namespace.c:3318 do_mount fs/namespace.c:3331 [inline] __do_sys_mount fs/namespace.c:3539 [inline] __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3516 __x64_sys_mount+0x63/0x70 fs/namespace.c:3516 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 0xffff888101c9d150 of 8 bytes by task 11874 on cpu 0: 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 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 value changed: 0x0000000000006496 -> 0x0000000000006497 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 11874 Comm: udevd Tainted: G W 5.15.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================