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BUG: KCSAN: data-race in __ext4_update_other_inode_time / __mark_inode_dirty

write to 0xffff8881409746c8 of 8 bytes by task 1810 on cpu 0:
 __mark_inode_dirty+0x223/0x6c0 fs/fs-writeback.c:2313
 generic_update_time fs/inode.c:1772 [inline]
 update_time fs/inode.c:1785 [inline]
 touch_atime+0x170/0x240 fs/inode.c:1856
 pick_link fs/namei.c:1723 [inline]
 step_into+0x869/0xec0 fs/namei.c:1798
 walk_component+0x190/0x350 fs/namei.c:1948
 lookup_last fs/namei.c:2397 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2421
 filename_lookup+0xff/0x390 fs/namei.c:2454
 user_path_at_empty+0x3b/0x50 fs/namei.c:2734
 user_path_at include/linux/namei.h:60 [inline]
 ksys_umount fs/namespace.c:1776 [inline]
 __do_sys_umount fs/namespace.c:1784 [inline]
 __se_sys_umount fs/namespace.c:1782 [inline]
 __x64_sys_umount+0x75/0xd0 fs/namespace.c:1782
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881409746c8 of 8 bytes by task 15185 on cpu 1:
 inode_is_dirtytime_only include/linux/fs.h:2423 [inline]
 __ext4_update_other_inode_time+0x48/0x5c0 fs/ext4/inode.c:4963
 ext4_update_other_inodes_time fs/ext4/inode.c:5006 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5135 [inline]
 ext4_mark_iloc_dirty+0x12b6/0x1750 fs/ext4/inode.c:5724
 __ext4_mark_inode_dirty+0x4db/0x5b0 fs/ext4/inode.c:5918
 ext4_dirty_inode+0x86/0xa0 fs/ext4/inode.c:5947
 __mark_inode_dirty+0x77/0x6c0 fs/fs-writeback.c:2274
 mark_inode_dirty include/linux/fs.h:2404 [inline]
 generic_write_end+0x157/0x180 fs/buffer.c:2223
 ext4_da_write_end+0x59b/0x730 fs/ext4/inode.c:3110
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3671
 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000000 -> 0x0000000000000800

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15185 Comm: syz-executor.1 Tainted: G        W         5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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