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BUG: KCSAN: data-race in __ext4_update_other_inode_time / writeback_single_inode

write to 0xffff88810c3e8cd8 of 8 bytes by task 31829 on cpu 1:
 writeback_single_inode+0x105/0x580 fs/fs-writeback.c:1577
 sync_inode fs/fs-writeback.c:2624 [inline]
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2644
 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
 ext4_sync_file+0x359/0x6e0 fs/ext4/fsync.c:170
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2843 [inline]
 ext4_buffered_write_iter+0x38f/0x3e0 fs/ext4/file.c:277
 ext4_file_write_iter+0x48a/0x10b0 fs/ext4/file.c:502
 call_write_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1319 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810c3e8cd8 of 8 bytes by task 8398 on cpu 0:
 inode_is_dirtytime_only include/linux/fs.h:2286 [inline]
 __ext4_update_other_inode_time+0x45/0x550 fs/ext4/inode.c:4965
 ext4_update_other_inodes_time fs/ext4/inode.c:5008 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5137 [inline]
 ext4_mark_iloc_dirty+0x1286/0x1700 fs/ext4/inode.c:5726
 __ext4_mark_inode_dirty+0x4db/0x5e0 fs/ext4/inode.c:5920
 __ext4_ext_dirty fs/ext4/extents.c:169 [inline]
 ext4_ext_remove_space+0x117f/0x1410 fs/ext4/extents.c:3016
 ext4_ext_truncate+0xfe/0x170 fs/ext4/extents.c:4370
 ext4_truncate+0x844/0xbd0 fs/ext4/inode.c:4264
 ext4_evict_inode+0xac6/0xef0 fs/ext4/inode.c:288
 evict+0x1aa/0x410 fs/inode.c:578
 iput_final fs/inode.c:1654 [inline]
 iput+0x3fd/0x520 fs/inode.c:1680
 dentry_unlink_inode+0x210/0x220 fs/dcache.c:374
 d_delete+0x78/0xa0 fs/dcache.c:2503
 vfs_rmdir+0x28a/0x2a0 fs/namei.c:3913
 do_rmdir+0x186/0x310 fs/namei.c:3962
 __do_sys_rmdir fs/namei.c:3980 [inline]
 __se_sys_rmdir fs/namei.c:3978 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3978
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8398 Comm: syz-executor.3 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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