FreeBSD Errata Notice FreeBSD-EN-16:15.vmbus
12 August, 2016 by email@example.com | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-16:15.vmbus Errata Notice The FreeBSD Project Topic: Better handle the GPADL setup failure in Hyper-V Category: core Module: vmbus Announced: 2016-08-12 Credits: Microsoft OSTC Affects: FreeBSD 10.3 Corrected: 2016-06-15 09:39:41 UTC (stable/10, 10.3-STABLE) 2016-08-12 04:01:16 UTC (releng/10.3, 10.3-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 FreeBSD guests on Hyper-V call hv_vmbus_post_message(), which uses hypercalls to post various types of VMBus messages to the Hyper-V host. One kind of the messages is to setup GPADL (Guest Physical Addrss Description List), which describes shared memory buffers between the host and the guest. II. Problem Description Most often, hv_vmbus_post_message() does not fail. However, it could fail intermittently when GPADLs of large shared memory is to be established with the host, such as on the hn(4) attach path, a GPADL of 15MB sendbuf is created, for which lots of messages will be flooded to the host. The host side tries to throttle the message rate by returning HV_STATUS_INSUFFICIENT_BUFFERS. Before this errata notice, several retries for failed messages would be attempted, but the delay between each retry is too low, causing sporadic message posting failure. A larger delay (>=1ms) is now used between each retry to fix the message posting failure. III. Impact Failures when Hyper-V network device driver are loaded and the device cannot work would occur. IV. Workaround No workaround is available, however FreeBSD virtual machines not running in Hyper-V or Azure are unaffected. V. Solution 1) Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot the system. 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 Afterward, reboot the system. 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. # fetch https://security.FreeBSD.org/patches/EN-16:15/vmbus.patch # fetch https://security.FreeBSD.org/patches/EN-16:15/vmbus.patch.asc # gpg --verify vmbus.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/ r301924 releng/10.3/ r303984 - ------------------------------------------------------------------------- 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 The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-16:15.vmbus.asc> -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJXrUskAAoJEO1n7NZdz2rnpSYQAOcdxWeTfHk3Pksvy8tZl1sE 1HzD7d4LUEd8TJZq6JA8JEmAA3MN6p0FoGDj0NlMviiy1slCo4BuEyriixhkKUqh be1+2pVY3d6gMixHFNPVKA0JB5amDvfxF8jY/lMZ1CsfD1tE0bTSRwPYhFFxJI8g QK2dbjbGPQF32fAh4953wLV/HO1n6JiQS8dtyJBc4BdGRNCcuZpl69lDeJJWH5Li IYtbQQlMIQZA5le7CjGXP+6eFus+U7CoqxuCq50CJwsgt0Rw+klApX85dodImlCR qn6FCB0OdM2W3KgrnOLEXjvmajUO1fWAkiwlS6ZlkqST5KSRUHC3pzzZcYrvLBtA qOslsoOp7v7uOvjKIt6As8KmX7OjFgNsiH4oxCL8H8HXNlN3uQRayMG8kglWqKWo QFjF5cPL1YnDn5cBSThGQY0QBnDFEPiyviJZZ8XInKAESNysOW5rpx4bLKRqz33L tZ0ebi+3PpA3M6wK9ag3zARJvqfTgHZ6KoVBF3HKmIB+LnyFQybHBaG5eG1sveWC 11KobiLoA1Te9v9KunJRBvmPMsV2zjrGJ5MYFw7UH/gYhjO2CGnRlJUCAHDFr7u+ f/AJYb9qSS6exSFGhl7tBAxEAQAizy2eCSde/rXqbNH8QPz4SM/J436GPdxcaTRD Lj+bkbcEPY6QqPPodDHn =JVB9 -----END PGP SIGNATURE----- _______________________________________________ firstname.lastname@example.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-announce To unsubscribe, send any mail to "email@example.com"