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BUG: KCSAN: data-race in __delayacct_blkio_end / __delayacct_blkio_start

write to 0xffff88812acf4b98 of 8 bytes by task 26812 on cpu 1:
 __delayacct_blkio_start+0x35/0x40 kernel/delayacct.c:61
 delayacct_blkio_start include/linux/delayacct.h:119 [inline]
 __schedule+0x18d/0x560 kernel/sched/core.c:4140
 schedule+0x91/0xd0 kernel/sched/core.c:4253
 io_schedule+0x3b/0x50 kernel/sched/core.c:5897
 wait_on_page_bit_common+0x484/0x760 mm/filemap.c:1150
 __lock_page+0x5f/0x70 mm/filemap.c:1358
 lock_page include/linux/pagemap.h:521 [inline]
 mpage_prepare_extent_to_map+0x2cd/0x650 fs/ext4/inode.c:2582
 ext4_writepages+0x682/0x1ef0 fs/ext4/inode.c:2736
 do_writepages+0x7b/0x150 mm/page-writeback.c:2354
 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:421
 __filemap_fdatawrite mm/filemap.c:429 [inline]
 filemap_flush+0x1f/0x30 mm/filemap.c:456
 ext4_alloc_da_blocks+0x4c/0x130 fs/ext4/inode.c:3146
 ext4_release_file+0x5b/0x1c0 fs/ext4/file.c:142
 __fput+0x1df/0x460 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:123
 get_signal+0x14e2/0x1520 kernel/signal.c:2533
 do_signal+0x25/0x270 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:212 [inline]
 __prepare_exit_to_usermode+0x127/0x230 arch/x86/entry/common.c:246
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:329
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812acf4b98 of 8 bytes by task 26788 on cpu 0:
 delayacct_end kernel/delayacct.c:48 [inline]
 __delayacct_blkio_end+0x70/0x100 kernel/delayacct.c:82
 delayacct_blkio_end include/linux/delayacct.h:125 [inline]
 try_to_wake_up+0x109/0x4d0 kernel/sched/core.c:2590
 autoremove_wake_function+0xc/0x50 kernel/sched/wait.c:389
 wake_page_function+0xb5/0xe0 mm/filemap.c:1027
 __wake_up_common+0xbc/0x130 kernel/sched/wait.c:93
 wake_up_page_bit+0xa4/0x190 mm/filemap.c:1047
 unlock_page+0x5e/0x70 mm/filemap.c:1292
 ext4_bio_write_page+0xc73/0xda0 fs/ext4/page-io.c:557
 mpage_submit_page fs/ext4/inode.c:2082 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2469 [inline]
 ext4_writepages+0xeb9/0x1ef0 fs/ext4/inode.c:2782
 do_writepages+0x7b/0x150 mm/page-writeback.c:2354
 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:421
 __filemap_fdatawrite mm/filemap.c:429 [inline]
 filemap_flush+0x1f/0x30 mm/filemap.c:456
 ext4_alloc_da_blocks+0x4c/0x130 fs/ext4/inode.c:3146
 ext4_release_file+0x5b/0x1c0 fs/ext4/file.c:142
 __fput+0x1df/0x460 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:216 [inline]
 __prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:246
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:329
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26788 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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