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BUG: KCSAN: data-race in dd_has_work / dd_insert_requests

write to 0xffff888103995c28 of 8 bytes by task 15024 on cpu 1:
 __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_schedule_flush_plug include/linux/blkdev.h:1280 [inline]
 io_schedule_prepare kernel/sched/core.c:6820 [inline]
 io_schedule+0x33/0x50 kernel/sched/core.c:6851
 bit_wait_io+0x8/0x50 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0xb6/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0xce/0x8a0 fs/jbd2/transaction.c:1076
 jbd2_journal_get_write_access+0x10c/0x1c0 fs/jbd2/transaction.c:1211
 __ext4_journal_get_write_access+0x17e/0x2c0 fs/ext4/ext4_jbd2.c:231
 ext4_ext_get_access fs/ext4/extents.c:142 [inline]
 ext4_ext_insert_extent+0x406/0x2bc0 fs/ext4/extents.c:1976
 ext4_ext_map_blocks+0x1597/0x1fd0 fs/ext4/extents.c:4259
 ext4_map_blocks+0x726/0xff0 fs/ext4/inode.c:637
 ext4_iomap_alloc fs/ext4/inode.c:3427 [inline]
 ext4_iomap_begin+0x513/0x6a0 fs/ext4/inode.c:3477
 iomap_apply+0x8d/0x4a0 fs/iomap/apply.c:46
 __iomap_dio_rw+0x448/0x9b0 fs/iomap/direct-io.c:517
 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 0xffff888103995c28 of 8 bytes by task 15026 on cpu 0:
 list_empty_careful include/linux/list.h:319 [inline]
 dd_has_work+0xfe/0x110 block/mq-deadline.c:590
 __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 block/blk-mq.c:1515 [inline]
 __blk_mq_delay_run_hw_queue+0x207/0x420 block/blk-mq.c:1592
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1645
 blk_mq_sched_insert_requests+0x144/0x210 block/blk-mq-sched.c:501
 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
 read_pages+0x3aa/0x6e0 mm/readahead.c:150
 page_cache_ra_unbounded+0x46c/0x4c0 mm/readahead.c:238
 ondemand_readahead+0x560/0x780 mm/readahead.c:267
 page_cache_sync_ra+0x18f/0x1a0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2361
 generic_file_buffered_read+0x26e/0x9c0 mm/filemap.c:2481
 generic_file_read_iter+0x82/0x3e0 mm/filemap.c:2633
 ext4_file_read_iter+0x2e0/0x430 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15026 Comm: syz-executor.4 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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