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BUG: KCSAN: data-race in dd_has_work / dd_insert_requests

write to 0xffff888102bed628 of 8 bytes by task 23918 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:521 [inline]
 dd_insert_requests+0x38e/0x4f0 block/mq-deadline.c:537
 blk_mq_sched_insert_requests+0xc3/0x210 block/blk-mq-sched.c:486
 blk_mq_flush_plug_list+0x2f5/0x400 block/blk-mq.c:1915
 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1755
 blk_finish_plug+0x44/0x60 block/blk-core.c:1772
 __iomap_dio_rw+0x60f/0x9b0 fs/iomap/direct-io.c:539
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:605
 ext4_dio_write_iter fs/ext4/file.c:552 [inline]
 ext4_file_write_iter+0xe6a/0x1060 fs/ext4/file.c:662
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x41a/0x770 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888102bed628 of 8 bytes by task 4853 on cpu 1:
 list_empty_careful include/linux/list.h:319 [inline]
 dd_has_work+0xfe/0x110 block/mq-deadline.c:590
 blk_mq_sched_has_work block/blk-mq-sched.h:75 [inline]
 blk_mq_hctx_has_pending block/blk-mq.c:74 [inline]
 blk_mq_run_hw_queue+0x1a4/0x260 block/blk-mq.c:1641
 blk_mq_submit_bio+0xd39/0x1040 block/blk-mq.c:2191
 __submit_bio_noacct_mq block/blk-core.c:1028 [inline]
 submit_bio_noacct+0x78d/0x960 block/blk-core.c:1061
 submit_bio+0x200/0x360 block/blk-core.c:1131
 submit_bh_wbc+0x39d/0x3e0 fs/buffer.c:3054
 submit_bh+0x21/0x30 fs/buffer.c:3060
 journal_submit_commit_record+0x42b/0x490 include/linux/jbd2.h:1345
 jbd2_journal_commit_transaction+0x1fae/0x32b0 fs/jbd2/commit.c:925
 kjournald2+0x263/0x480 fs/jbd2/journal.c:213
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4853 Comm: jbd2/sda1-8 Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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