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BUG: KCSAN: data-race in __delayacct_blkio_end / __delayacct_blkio_start

write to 0xffff88810155bd78 of 8 bytes by task 15415 on cpu 0:
 __delayacct_blkio_start+0x35/0x40 kernel/delayacct.c:61
 delayacct_blkio_start include/linux/delayacct.h:119 [inline]
 __schedule+0x18c/0x550 kernel/sched/core.c:4485
 schedule+0x7f/0xb0 kernel/sched/core.c:4601
 io_schedule+0x3b/0x50 kernel/sched/core.c:6295
 wait_on_page_bit_common+0x633/0x910 mm/filemap.c:1273
 wait_on_page_bit+0x3f/0x50 mm/filemap.c:1334
 wait_on_page_writeback+0x72/0x130 mm/page-writeback.c:2837
 __filemap_fdatawait_range+0xdd/0x1b0 mm/filemap.c:527
 file_write_and_wait_range+0xea/0x120 mm/filemap.c:765
 ext4_sync_file+0xf4/0x6a0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2723 [inline]
 ext4_buffered_write_iter+0x384/0x3d0 fs/ext4/file.c:278
 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
 call_write_iter include/linux/fs.h:1887 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4b0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x42a/0x780 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+0x574/0xb70 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 0xffff88810155bd78 of 8 bytes by interrupt on cpu 1:
 delayacct_end kernel/delayacct.c:48 [inline]
 __delayacct_blkio_end+0x70/0xf0 kernel/delayacct.c:82
 delayacct_blkio_end include/linux/delayacct.h:125 [inline]
 try_to_wake_up+0x107/0x470 kernel/sched/core.c:2892
 wake_page_function+0xd9/0x200 mm/filemap.c:1080
 __wake_up_common+0xbc/0x130 kernel/sched/wait.c:93
 wake_up_page_bit+0xa4/0x190 mm/filemap.c:1113
 wake_up_page mm/filemap.c:1154 [inline]
 end_page_writeback+0xeb/0x110 mm/filemap.c:1491
 ext4_finish_bio+0x429/0x490 fs/ext4/page-io.c:146
 ext4_end_bio+0x1ba/0x310 fs/ext4/page-io.c:367
 bio_endio+0x28b/0x350 block/bio.c:1450
 req_bio_endio block/blk-core.c:263 [inline]
 blk_update_request+0x4d5/0xb00 block/blk-core.c:1467
 scsi_end_request+0x51/0x470 drivers/scsi/scsi_lib.c:569
 scsi_io_completion+0x105/0xfb0 drivers/scsi/scsi_lib.c:965
 scsi_finish_command+0x26c/0x2b0 drivers/scsi/scsi.c:214
 scsi_softirq_done+0xdf/0x440 drivers/scsi/scsi_lib.c:1443
 blk_done_softirq+0x145/0x190 block/blk-mq.c:586
 __do_softirq+0x12c/0x2b1 kernel/softirq.c:298
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu+0xb2/0xc0 kernel/softirq.c:423
 common_interrupt+0xb5/0x130 arch/x86/kernel/irq.c:239
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:622
 native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline]
 arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline]
 kcsan_setup_watchpoint+0x1ec/0x4d0 kernel/kcsan/core.c:591
 __tlb_adjust_range include/asm-generic/tlb.h:310 [inline]
 tlb_flush_pte_range include/asm-generic/tlb.h:521 [inline]
 zap_pte_range+0x399/0x13c0 mm/memory.c:1239
 zap_pmd_range mm/memory.c:1357 [inline]
 zap_pud_range mm/memory.c:1386 [inline]
 zap_p4d_range mm/memory.c:1407 [inline]
 unmap_page_range+0x560/0x660 mm/memory.c:1428
 unmap_single_vma+0x157/0x210 mm/memory.c:1473
 unmap_vmas+0xbf/0x150 mm/memory.c:1505
 exit_mmap+0x1c7/0x3b0 mm/mmap.c:3222
 __mmput+0xa2/0x220 kernel/fork.c:1079
 mmput+0x38/0x40 kernel/fork.c:1100
 exit_mm+0x2bd/0x320 kernel/exit.c:483
 do_exit+0x3c2/0x15a0 kernel/exit.c:793
 do_group_exit+0xc8/0x170 kernel/exit.c:903
 get_signal+0xf9b/0x1510 kernel/signal.c:2758
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15417 Comm: syz-executor.2 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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