The __get_user_asm_ex macro in arch/x86/include/asm/uaccess.h in the Linux kernel before 4.7.5 does not initialize a certain integer variable, which allows local users to obtain sensitive information from kernel stack memory by triggering failure of a get_user_ex call.
https://github.com/torvalds/linux/commit/1c109fabbd51863475cd12ac206bdd249aee35af
https://bugzilla.redhat.com/show_bug.cgi?id=1391908
http://www.securityfocus.com/bid/94144
http://www.openwall.com/lists/oss-security/2016/11/04/4