syzbot

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BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_run_hw_queue

write to 0xffff88810293ea10 of 8 bytes by task 73 on cpu 1:
 INIT_LIST_HEAD include/linux/list.h:38 [inline]
 list_splice_init include/linux/list.h:492 [inline]
 __blk_mq_sched_dispatch_requests+0x137/0x270 block/blk-mq-sched.c:287
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:339
 __blk_mq_run_hw_queue+0x7e/0x100 block/blk-mq.c:1980
 __blk_mq_delay_run_hw_queue+0x19c/0x390 block/blk-mq.c:2057
 blk_mq_run_hw_queue+0x180/0x310 block/blk-mq.c:2108
 blk_mq_run_hw_queues+0x1c0/0x240 block/blk-mq.c:2171
 blk_mq_requeue_work+0x3bd/0x3f0 block/blk-mq.c:1321
 process_one_work+0x3e3/0x970 kernel/workqueue.c:2289
 worker_thread+0x638/0xaa0 kernel/workqueue.c:2436
 kthread+0x1c1/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffff88810293ea10 of 8 bytes by task 27027 on cpu 0:
 list_empty_careful include/linux/list.h:329 [inline]
 blk_mq_hctx_has_pending block/blk-mq.c:101 [inline]
 blk_mq_run_hw_queue+0x19b/0x310 block/blk-mq.c:2103
 blk_mq_sched_insert_requests+0x1cc/0x2a0 block/blk-mq-sched.c:493
 blk_mq_dispatch_plug_list+0x1e9/0x2c0 block/blk-mq.c:2603
 blk_mq_flush_plug_list+0x2ea/0x340 block/blk-mq.c:2645
 __blk_flush_plug+0x25a/0x2b0 block/blk-core.c:1244
 blk_finish_plug+0x44/0x60 block/blk-core.c:1268
 read_pages+0x788/0x7f0 mm/readahead.c:179
 page_cache_ra_unbounded+0x134/0x310 mm/readahead.c:234
 ondemand_readahead+0x4d3/0x770
 page_cache_sync_ra+0x198/0x1b0 mm/readahead.c:692
 page_cache_sync_readahead include/linux/pagemap.h:1185 [inline]
 filemap_get_pages mm/filemap.c:2598 [inline]
 filemap_read+0x3d5/0xe10 mm/filemap.c:2685
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2831
 call_read_iter include/linux/fs.h:2044 [inline]
 generic_file_splice_read+0x1de/0x2c0 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888102fa9848 -> 0xffff88810293ea08

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27027 Comm: syz-executor.4 Not tainted 5.18.0-rc1-syzkaller-00016-g3e732ebf7316-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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