syzbot

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BUG: KCSAN: data-race in dd_has_work / deadline_remove_request

write to 0xffff888121eede18 of 8 bytes by task 26273 on cpu 0:
 __list_del include/linux/list.h:112 [inline]
 __list_del_entry include/linux/list.h:135 [inline]
 list_del_init include/linux/list.h:204 [inline]
 deadline_remove_request+0x6a/0x180 block/mq-deadline.c:113
 deadline_move_request block/mq-deadline.c:176 [inline]
 __dd_dispatch_request block/mq-deadline.c:365 [inline]
 dd_dispatch_request+0x6d2/0x740 block/mq-deadline.c:387
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:161 [inline]
 blk_mq_do_dispatch_sched+0x1df/0x610 block/blk-mq-sched.c:214
 __blk_mq_sched_dispatch_requests+0x1fd/0x2a0 block/blk-mq-sched.c:325
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:356
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1534
 __blk_mq_delay_run_hw_queue+0x199/0x340 block/blk-mq.c:1611
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1664
 blk_mq_sched_insert_requests+0x14d/0x200 block/blk-mq-sched.c:610
 blk_mq_flush_plug_list+0x2f5/0x420 block/blk-mq.c:1934
 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1868
 blk_finish_plug+0x44/0x60 block/blk-core.c:1885
 read_pages+0x3b5/0x700 mm/readahead.c:150
 page_cache_readahead_unbounded+0x41a/0x470 mm/readahead.c:244
 ondemand_readahead+0x4e4/0x6e0 mm/readahead.c:273
 page_cache_sync_readahead+0x178/0x1a0 mm/readahead.c:585
 generic_file_buffered_read+0x2ec/0x1f60 mm/filemap.c:2199
 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2503
 call_read_iter include/linux/fs.h:1876 [inline]
 generic_file_splice_read+0x22b/0x310 fs/splice.c:312
 do_splice_to fs/splice.c:870 [inline]
 splice_direct_to_actor+0x2a8/0x660 fs/splice.c:950
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x56a/0xba0 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888121eede18 of 8 bytes by task 26262 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:150 [inline]
 blk_mq_do_dispatch_sched+0x138/0x610 block/blk-mq-sched.c:214
 __blk_mq_sched_dispatch_requests+0x1fd/0x2a0 block/blk-mq-sched.c:325
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:356
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1534
 __blk_mq_delay_run_hw_queue+0x199/0x340 block/blk-mq.c:1611
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1664
 blk_mq_sched_insert_requests+0x14d/0x200 block/blk-mq-sched.c:610
 blk_mq_flush_plug_list+0x2f5/0x420 block/blk-mq.c:1934
 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1868
 blk_finish_plug+0x44/0x60 block/blk-core.c:1885
 do_blockdev_direct_IO+0xc18/0x1300 fs/direct-io.c:1336
 __blockdev_direct_IO+0x5e/0x70 fs/direct-io.c:1393
 blockdev_direct_IO include/linux/fs.h:3095 [inline]
 fat_direct_IO+0x108/0x1c0 fs/fat/inode.c:288
 generic_file_direct_write+0x25e/0x3e0 mm/filemap.c:3400
 __generic_file_write_iter+0x19c/0x330 mm/filemap.c:3587
 generic_file_write_iter+0x2f3/0x3e0 mm/filemap.c:3662
 call_write_iter include/linux/fs.h:1882 [inline]
 do_iter_readv_writev+0x32e/0x3d0 fs/read_write.c:713
 do_iter_write+0x112/0x4b0 fs/read_write.c:1018
 vfs_iter_write+0x4c/0x70 fs/read_write.c:1059
 iter_file_splice_write+0x41a/0x770 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x95/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x56a/0xba0 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 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: 1 PID: 26262 Comm: syz-executor.0 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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