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BUG: KCSAN: data-race in dd_has_work / dd_insert_requests

write to 0xffff88810258c718 of 8 bytes by task 10860 on cpu 0:
 __list_add include/linux/list.h:70 [inline]
 list_add_tail include/linux/list.h:100 [inline]
 dd_insert_request block/mq-deadline.c:519 [inline]
 dd_insert_requests+0x390/0x4f0 block/mq-deadline.c:535
 blk_mq_sched_insert_request+0x22c/0x280 block/blk-mq-sched.c:458
 blk_mq_submit_bio+0x8b1/0x1060 block/blk-mq.c:2243
 __submit_bio_noacct_mq block/blk-core.c:1013 [inline]
 submit_bio_noacct+0x7c2/0x9a0 block/blk-core.c:1046
 submit_bio+0x200/0x370 block/blk-core.c:1117
 submit_bh_wbc+0x36b/0x3b0 fs/buffer.c:3054
 ll_rw_block+0x12e/0x180 fs/buffer.c:3060
 reiserfs_breada fs/reiserfs/journal.c:2344 [inline]
 journal_read fs/reiserfs/journal.c:2447 [inline]
 journal_init+0x195f/0x3130 fs/reiserfs/journal.c:2881
 reiserfs_fill_super+0x850/0x1bc0 fs/reiserfs/super.c:2032
 mount_bdev+0x1e8/0x290 fs/super.c:1367
 get_super_block+0x2d/0x40 fs/reiserfs/super.c:2606
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:592
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1497
 do_new_mount fs/namespace.c:2916 [inline]
 path_mount+0x11b9/0x1c00 fs/namespace.c:3246
 do_mount fs/namespace.c:3259 [inline]
 __do_sys_mount fs/namespace.c:3467 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3444
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3444
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810258c718 of 8 bytes by task 10865 on cpu 1:
 list_empty_careful include/linux/list.h:319 [inline]
 dd_has_work+0x98/0xe0 block/mq-deadline.c:583
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:135 [inline]
 blk_mq_do_dispatch_sched+0x138/0x610 block/blk-mq-sched.c:199
 __blk_mq_sched_dispatch_requests+0x1fd/0x2a0 block/blk-mq-sched.c:310
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:341
 __blk_mq_run_hw_queue+0xc1/0x140 block/blk-mq.c:1488
 __blk_mq_delay_run_hw_queue+0x188/0x330 block/blk-mq.c:1565
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1618
 blk_mq_sched_insert_requests+0x144/0x210 block/blk-mq-sched.c:501
 blk_mq_flush_plug_list+0x2f5/0x400 block/blk-mq.c:1942
 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1748
 blk_finish_plug+0x44/0x60 block/blk-core.c:1765
 read_pages+0x3aa/0x6e0 mm/readahead.c:150
 page_cache_ra_unbounded+0x46c/0x4c0 mm/readahead.c:238
 do_page_cache_ra mm/readahead.c:267 [inline]
 force_page_cache_ra+0x226/0x260 mm/readahead.c:298
 page_cache_sync_ra+0x178/0x1a0 mm/readahead.c:572
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2367
 generic_file_buffered_read+0x26e/0x9c0 mm/filemap.c:2487
 generic_file_read_iter+0x82/0x3e0 mm/filemap.c:2639
 blkdev_read_iter+0xb3/0xc0 fs/block_dev.c:1714
 call_read_iter include/linux/fs.h:1971 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x565/0x5d0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10865 Comm: systemd-udevd Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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