(RHSA-2016:2132) Important: kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

• A race condition was found in the way the Linux kernel’s memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged, local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system. (CVE-2016-5195, Important)

Red Hat would like to thank Phil Oester for reporting this issue.

Bug Fix(es):

• Previously, the BUG_ON() signal appeared in the fs_clear_inode() function where the nfs_have_writebacks() function reported a positive value for nfs_inode->npages. As a consequence, a kernel panic occurred. The provided patch performs a serialization by holding the inode i_lock over the check of PagePrivate and locking the request, which fixes this bug. (BZ#1365157)