Race condition in the scan_get_next_rmap_item function in mm/ksm.c in the Linux kernel before 2.6.39.3, when Kernel SamePage Merging (KSM) is enabled, allows local users to cause a denial of service (NULL pointer dereference) or possibly have unspecified other impact via a crafted application.
https://github.com/torvalds/linux/commit/2b472611a32a72f4a118c069c2d62a1a3f087afd
https://bugzilla.redhat.com/show_bug.cgi?id=710338
http://www.openwall.com/lists/oss-security/2011/06/06/1
http://ftp.osuosl.org/pub/linux/kernel/v2.6/ChangeLog-2.6.39.3