syzbot

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BUG: KCSAN: data-race in blk_mq_sched_dispatch_requests / blk_mq_sched_dispatch_requests

read-write to 0xffff8881030aef58 of 8 bytes by task 4339 on cpu 1:
 blk_mq_sched_dispatch_requests+0x84/0x100 block/blk-mq-sched.c:327
 blk_mq_run_hw_queue+0x290/0x4b0 block/blk-mq.c:2249
 blk_mq_flush_plug_list+0x9d3/0xc00 block/blk-mq.c:2783
 __blk_flush_plug+0x223/0x280 block/blk-core.c:1144
 blk_finish_plug+0x47/0x60 block/blk-core.c:1168
 __iomap_dio_rw+0xd28/0x1100 fs/iomap/direct-io.c:606
 iomap_dio_rw+0x40/0x90 fs/iomap/direct-io.c:688
 ext4_dio_read_iter fs/ext4/file.c:94 [inline]
 ext4_file_read_iter+0x210/0x290 fs/ext4/file.c:145
 call_read_iter include/linux/fs.h:1862 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:419
 do_splice_to fs/splice.c:902 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:973
 do_splice_direct+0x104/0x180 fs/splice.c:1082
 do_sendfile+0x3b8/0x950 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read-write to 0xffff8881030aef58 of 8 bytes by task 4341 on cpu 0:
 blk_mq_sched_dispatch_requests+0x84/0x100 block/blk-mq-sched.c:327
 blk_mq_run_hw_queue+0x290/0x4b0 block/blk-mq.c:2249
 blk_mq_flush_plug_list+0x9d3/0xc00 block/blk-mq.c:2783
 __blk_flush_plug+0x223/0x280 block/blk-core.c:1144
 blk_finish_plug+0x47/0x60 block/blk-core.c:1168
 ext4_do_writepages+0x1c88/0x21e0 fs/ext4/inode.c:2754
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2792
 do_writepages+0x1c5/0x340 mm/page-writeback.c:2551
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:390
 __filemap_fdatawrite_range mm/filemap.c:423 [inline]
 filemap_write_and_wait_range+0xe6/0x220 mm/filemap.c:678
 __iomap_dio_rw+0x5dc/0x1100 fs/iomap/direct-io.c:569
 iomap_dio_rw+0x40/0x90 fs/iomap/direct-io.c:688
 ext4_dio_read_iter fs/ext4/file.c:94 [inline]
 ext4_file_read_iter+0x210/0x290 fs/ext4/file.c:145
 call_read_iter include/linux/fs.h:1862 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:419
 do_splice_to fs/splice.c:902 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:973
 do_splice_direct+0x104/0x180 fs/splice.c:1082
 do_sendfile+0x3b8/0x950 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000000008bd -> 0x00000000000008be

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4341 Comm: syz-executor.4 Not tainted 6.4.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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syz-executor.4 (4341) used greatest stack depth: 9960 bytes left