fs/ext4/inode.c in the Linux kernel before 4.6.2, when ext4 data=ordered mode is used, mishandles a needs-flushing-before-commit list, which allows local users to obtain sensitive information from other users' files in opportunistic circumstances by waiting for a hardware reset, creating a new file, making write system calls, and reading this file.
https://source.android.com/security/bulletin/2017-09-01
https://github.com/torvalds/linux/commit/06bd3c36a733ac27962fea7d6f47168841376824
https://bugzilla.redhat.com/show_bug.cgi?id=1450261
http://www.securityfocus.com/bid/98491
http://www.openwall.com/lists/oss-security/2017/05/15/2