================================================================== BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf write to 0xffff88814b861a38 of 8 bytes by task 22338 on cpu 0: relay_switch_subbuf+0x3b5/0x3c0 kernel/relay.c:711 relay_reserve include/linux/relay.h:248 [inline] __blk_add_trace+0x66f/0x740 kernel/trace/blktrace.c:275 blk_add_trace_bio kernel/trace/blktrace.c:896 [inline] blk_add_trace_bio_queue+0xb1/0xc0 kernel/trace/blktrace.c:928 trace_block_bio_queue include/trace/events/block.h:332 [inline] submit_bio_checks+0x8a5/0x8e0 block/blk-core.c:819 blk_mq_get_request block/blk-mq.c:2590 [inline] blk_mq_submit_bio+0x2e8/0x14e0 block/blk-mq.c:2632 __submit_bio+0x131/0x340 block/blk-core.c:849 __submit_bio_noacct_mq block/blk-core.c:924 [inline] submit_bio_noacct+0x418/0x4e0 block/blk-core.c:950 submit_bio+0x10c/0x180 ext4_io_submit+0xcd/0xf0 fs/ext4/page-io.c:379 ext4_writepages+0x780/0x1e80 fs/ext4/inode.c:2753 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364 filemap_fdatawrite_wbc mm/filemap.c:407 [inline] __filemap_fdatawrite_range mm/filemap.c:440 [inline] file_write_and_wait_range+0x132/0x1d0 mm/filemap.c:824 ext4_sync_file+0x105/0x6e0 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:182 generic_write_sync include/linux/fs.h:2956 [inline] ext4_buffered_write_iter+0x322/0x380 fs/ext4/file.c:277 ext4_file_write_iter+0x2e7/0x1200 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725 do_iter_write+0x192/0x5c0 fs/read_write.c:851 vfs_iter_write+0x4c/0x70 fs/read_write.c:892 iter_file_splice_write+0x43a/0x790 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0x106/0x190 fs/splice.c:979 do_sendfile+0x675/0xc40 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1304 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae write to 0xffff88814b861a38 of 8 bytes by task 22329 on cpu 1: relay_switch_subbuf+0x3b5/0x3c0 kernel/relay.c:711 relay_reserve include/linux/relay.h:248 [inline] __blk_add_trace+0x66f/0x740 kernel/trace/blktrace.c:275 blk_add_trace_rq kernel/trace/blktrace.c:836 [inline] blk_add_trace_rq_issue+0xf8/0x110 kernel/trace/blktrace.c:850 trace_block_rq_issue include/trace/events/block.h:204 [inline] blk_mq_start_request+0x247/0x290 block/blk-mq.c:1030 scsi_queue_rq+0x1177/0x1460 drivers/scsi/scsi_lib.c:1707 blk_mq_dispatch_rq_list+0x534/0x11e0 block/blk-mq.c:1662 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:199 [inline] blk_mq_do_dispatch_sched+0x446/0x6d0 block/blk-mq-sched.c:212 __blk_mq_sched_dispatch_requests+0x1ca/0x270 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:358 __blk_mq_run_hw_queue+0xc1/0x140 block/blk-mq.c:1784 __blk_mq_delay_run_hw_queue+0x199/0x360 block/blk-mq.c:1861 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1914 blk_mq_sched_insert_requests+0x130/0x200 block/blk-mq-sched.c:511 blk_mq_flush_plug_list+0x372/0x460 block/blk-mq.c:2291 blk_flush_plug+0x25a/0x2b0 block/blk-core.c:1590 blk_finish_plug+0x44/0x60 block/blk-core.c:1614 ext4_writepages+0x1981/0x1e80 fs/ext4/inode.c:2846 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364 filemap_fdatawrite_wbc mm/filemap.c:407 [inline] __filemap_fdatawrite_range mm/filemap.c:440 [inline] file_write_and_wait_range+0x132/0x1d0 mm/filemap.c:824 ext4_sync_file+0x105/0x6e0 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:182 generic_write_sync include/linux/fs.h:2956 [inline] ext4_buffered_write_iter+0x322/0x380 fs/ext4/file.c:277 ext4_file_write_iter+0x2e7/0x1200 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725 do_iter_write+0x192/0x5c0 fs/read_write.c:851 vfs_iter_write+0x4c/0x70 fs/read_write.c:892 iter_file_splice_write+0x43a/0x790 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0x106/0x190 fs/splice.c:979 do_sendfile+0x675/0xc40 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1304 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000000000000040 -> 0x0000000000000030 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 22329 Comm: syz-executor.3 Tainted: G W 5.16.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== syz-executor.3 (22329) used greatest stack depth: 8960 bytes left