FreeBSD Errata Notices
2016-Oct-25 17:37 UTC
[FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-16:17.vm
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================FreeBSD-EN-16:17.vm Errata Notice The FreeBSD Project Topic: Virtual Memory issues Category: core Module: Virtual Memory subsystem Announced: 2016-10-25 Credits: Affects: FreeBSD 10.3 Corrected: 2016-07-25 13:31:18 UTC (stable/10, 10.3-STABLE) 2016-10-25 16:45:55 UTC (releng/10.3, 10.3-RELEASE-p11) For general information regarding FreeBSD Errata Notices and Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.freebsd.org/>. I. Background The virtual memory subsystem manages address spaces of the processes, and tightly cooperates with the file systems and process management to provide the execution environment for the applications. II. Problem Description Due to increased parallelism and optimizations in several parts of the system, the previously latent bugs in VM become much easier to trigger, affecting a significant number of the FreeBSD users. The exact technical details of the issues are provided in the commit messages of the merged revisions, which are listed below with short summaries. r301184 prevent parallel object collapses, fixes object lifecycle r301436 do not leak the vm object lock, fixes overcommit disable r302243 avoid the active object marking for vm.vmtotal sysctl, fixes "vodead" hangs r302513 vm_fault() race with the vm_object_collapse(), fixes spurious SIGSEGV r303291 postpone BO_DEAD, fixes panic on fast vnode reclaim III. Impact Due to the bugs, spurious SIGSEGV might be delivered to processes, causing hangs on the "vodead" state on filesystem operations might be observed, system might hang or panic during rapid UFS vnodes reclamation. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your present system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 3) To update your present system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. [FreeBSD 10.3] # fetch https://security.FreeBSD.org/patches/EN-16:17/vm.patch # fetch https://security.FreeBSD.org/patches/EN-16:17/vm.patch.asc # gpg --verify vm.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/10/ r303291 releng/10.3/ r307929 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204764> <URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204426> The latest revision of this Errata Notice is available at https://security.FreeBSD.org/advisories/FreeBSD-EN-16:17.vm.asc -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJYD5UUAAoJEO1n7NZdz2rnxWUQAJ/yL3KpTFuhaHnnOg84mpwE KguSEpFB4BqxPVntuwuutyvRf1aibdrcjOESJ62U86Nw3Yn+umYFQaq6ySTzWhbY 6JlARZEGQa0kt+kP8etx1Z/AjCiplHFjhi1HSdq/nhnYwwVlrw5vu5IiN66Vu9vu OyfjmC3Zxx9Zf8CByTk7S9qGzhrsJPZvlkgVnOgUEwEq+zbYFAYk+vNVvF7KwSI5 WxlOhkt6OdJUTUV+lOl5xZlGU3LlvE+2/+LpOOyNbgK/alAuPpt3JGiVnRYje6YI lQnJXdM6Y5cITawkOhaePNRlgIphSKOjiomlVfpzDVKaoEvKTaTA0QNcTG7cF5vD AeO/k2J15ARJQo/SRmTGE2/kOC7RSlAPBAYcBYy83LXDRxrhWtkz12LHzGu85IBy TzgWgJX9IBiQDXKBg+7BLzkWAb4lX5sg38fZzGn80GD2EhkZ8vSnzjQyCgVQdxKD T4XVVbiRSDywxelhRI9L/xLTM8kPNbL4ZQLrtS5VvQt/PSNubcFMkLgvP+lbOvKB eE44FX8jQrs5YNbFamksOHJ6qDSzQk4Rxk6Nd6BlYAD/xFT+h5MnqydBtl4cWua1 zpaCUjqA2OxQHANiauFRj71fjjWfKF/pbEsfHaJmtyx55PyVwhgeATjbo02kuWug sk7U5vuJxdMO+iRBHQKZ =Jq+g -----END PGP SIGNATURE-----