Date: Wed, 19 Dec 2018 20:52:49 +0000 (UTC) From: FreeBSD Errata Notices <errata-notices@freebsd.org> To: FreeBSD Errata Notices <errata-notices@freebsd.org> Subject: [FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-18:18.zfs Message-ID: <20181219205249.CB31819B70@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-18:18.zfs Errata Notice The FreeBSD Project Topic: ZFS vnode reclaim deadlock Category: core Module: kernel Announced: 2018-12-19 Credits: Allan Jude Affects: FreeBSD 11.2 Corrected: 2018-12-11 19:34:25 UTC (stable/11, 11.2-STABLE) 2018-12-19 18:05:50 UTC (releng/11.2, 11.2-RELEASE-p7) 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 ZFS is one of several filesystems available on FreeBSD. ZFS supports many advanced features, including checksumming, transparent compression, and snapshots. ZFS saves synchronous writes to the ZFS Intent Log (ZIL), which may be a separate log device (SLOG), so they can be replayed in the event of a power failure or system crash. This ensures that the contents of write() calls that succeeded will still be available after the system unexpectedly reboots. II. Problem Description There is a possible deadlock between zil_commit() and zfs_zget() during the vnode reclaim process. If zfs_zget() is not able to take the vnode exclusive lock, it will retry indefinately, blocking forward progress. III. Impact Processes may hang on the waitchan "zilog->zl_writer_lock". IV. Workaround Increasing the maximum number of vnodes (kern.maxvnodes) may decrease the frequency of this deadlock. Systems not using ZFS are not affected. 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 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 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 11.2] # fetch https://security.FreeBSD.org/patches/EN-18:18/zfs.patch # fetch https://security.FreeBSD.org/patches/EN-18:18/zfs.patch.asc # gpg --verify zfs.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/11/ r341828 releng/11.2/ r342226 - ------------------------------------------------------------------------- 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=229614> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-18:18.zfs.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAlwan2pfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cLKthAAq0CXErX6YRoMafBIhnMBgE+07l0FuIS0iHewgcf47jpTdmYp5BKk4n5Z VUM9vo3zETHXmjedV3drTbJEQWG3H30R8P964YEPoUQjQ4D/AG+hlRKTerGkJx/w CMMpSZEnRR5JDLrGaB2NfBKUu0s9sPWFMGbgOWYDxxiUUS5NwSYHPlaIu6MB4SXv AyTwLLlCXf7sH+oQrosu4Pw4emQzEGP41I0N0Nt8Z+kvJdzQd32xGP1M/OsW29LL SOZfXhERhwVx/2AYmOorkyVuHh1Q8OXbYckxfAXdKgRMm6rOEk3ZdPEH+lVTTw4l RmFmz5AwU5icDAeILGNjiEPzeF3w8KT1x39CnSB5oofbnDEXcGsL92lHtQY3kkbK PbUoJmjiGMwGr63HxU+CoR3meG8LJIHK1Bn/D3tSUs1GAZQHYbH6Vv/O2cidWxeD /hIxffhSbuaN9lMy4gV8wQdxSRz/Am3AsYNVlS9EvCCvwB4lYZOf0GeEhgLFX56h 4w0XGBKy6FE/SHrNALWsyCJCnP1gN3njx/jwL8Dp3Vyqmft06w0KHw/xb5InYk4r VPn+j1DkfWV97Gi8l+T8B7ir9W3KRDOlJUwInzeKRPojebdxlorM6BFtFsf90dXs 2xD1j/6m7RDqm+rGYPk6CdFJh95M5Roz0WJ1uCs89mpEHofW1kE= =Gqpb -----END PGP SIGNATURE-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20181219205249.CB31819B70>