The __clear_user function in arch/arm64/lib/clear_user.S in the Linux kernel before 3.17.4 on the ARM64 platform allows local users to cause a denial of service (system crash) by reading one byte beyond a /dev/zero page boundary.
https://github.com/torvalds/linux/commit/97fc15436b36ee3956efad83e22a557991f7d19d
https://bugzilla.redhat.com/show_bug.cgi?id=1163744
http://www.securityfocus.com/bid/71082
http://www.openwall.com/lists/oss-security/2014/11/13/5
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.17.4