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BUG: KCSAN: data-race in ext4_mark_iloc_dirty / generic_update_time

write to 0xffff888128a3a650 of 16 bytes by task 8347 on cpu 1:
 generic_update_time+0x109/0x270 fs/inode.c:1660
 update_time fs/inode.c:1683 [inline]
 file_update_time+0x237/0x300 fs/inode.c:1898
 __generic_file_write_iter+0x132/0x380 mm/filemap.c:3384
 ext4_file_write_iter+0x1bd/0xa00 fs/ext4/file.c:268
 call_write_iter include/linux/fs.h:1895 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 __kernel_write+0xb8/0x240 fs/read_write.c:515
 do_acct_process+0x9d9/0xba0 kernel/acct.c:520
 acct_pin_kill+0x2e/0xb0 kernel/acct.c:174
 pin_kill+0xfe/0x2a0 fs/fs_pin.c:44
 acct_on+0x350/0x440 kernel/acct.c:254
 __do_sys_acct kernel/acct.c:286 [inline]
 __se_sys_acct kernel/acct.c:273 [inline]
 __x64_sys_acct+0x97/0x110 kernel/acct.c:273
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888128a3a658 of 8 bytes by task 8326 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:5265 [inline]
 ext4_mark_iloc_dirty+0x495/0x1580 fs/ext4/inode.c:5876
 ext4_mark_inode_dirty+0xe9/0x420 fs/ext4/inode.c:6055
 mpage_map_and_submit_extent fs/ext4/inode.c:2578 [inline]
 ext4_writepages+0x17b0/0x2300 fs/ext4/inode.c:2869
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1c5/0x230 mm/filemap.c:421
 filemap_write_and_wait_range mm/filemap.c:681 [inline]
 filemap_write_and_wait_range+0xb1/0x150 mm/filemap.c:675
 ext4_punch_hole+0x175/0xab0 fs/ext4/inode.c:4270
 ext4_fallocate+0x2bc/0x13d0 fs/ext4/extents.c:4889
 vfs_fallocate+0x3be/0x650 fs/open.c:309
 ksys_fallocate+0x61/0xa0 fs/open.c:332
 __do_sys_fallocate fs/open.c:340 [inline]
 __se_sys_fallocate fs/open.c:338 [inline]
 __x64_sys_fallocate+0x5e/0x80 fs/open.c:338
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8326 Comm: syz-executor.3 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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