FreeBSD Errata Notice FreeBSD-EN-20:11.ena
9 June, 2020 by email@example.com | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-20:11.ena Errata Notice The FreeBSD Project Topic: Stability issues in ena(4) driver Category: core Module: ena Announced: 2020-06-09 Credits: Colin Percival Affects: FreeBSD 12.1 Corrected: 2020-05-12 18:44:41 UTC (stable/12, 12.1-STABLE) 2020-06-09 16:10:57 UTC (releng/12.1, 12.1-RELEASE-p6) 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 ena(4) driver is used to access the Elastic Network Adapter network interface on recent Amazon Elastic Compute Cloud (EC2) instances. It is designed to make full use of the EC2 network, operating at up to 100 Gbps. II. Problem Description The ena(4) driver attempts to allocate a large number of 16 kB mbuf clusters to use as buffers for received packets. Under low memory conditions, the process of attempting to allocate these buffers may take a long time. On FreeBSD 12.x, these allocations are attempted from an interrupt thread running at high priority, and can subsequently starve other parts of the system of CPU time. It appears that systems using the ZFS filesystem may be more likely to experience this issue, possibly due to the memory pressure created by the allocation of memory to the ZFS ARC. III. Impact The system may become unresponsive, appearing to "lock up" for periods of several seconds. The ena(4) driver may log errors such as The number of lost tx completion is above the threshold (129 > 128). and reset the device; the nvme(4) driver may also experience timeouts resulting in a range of errors being reported and the device being reset, and in some cases causing kernel panics. IV. Workaround No workaround is available. Systems which are not part of the Amazon Elastic Compute Cloud (EC2) are not affected; nor are older EC2 instance types, which lack the Elastic Network Adapter hardware. V. Solution Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot. Perform one of the following: 1) 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 # shutdown -r +10min "Rebooting for errata update" 2) 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 12.1] # fetch https://security.FreeBSD.org/patches/EN-20:11/ena.patch # fetch https://security.FreeBSD.org/patches/EN-20:11/ena.patch.asc # gpg --verify ena.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. NOTE: This patch can have a small (~2%) impact on the throughput of the ena(4) device. The original performance can be restored -- at the expense of latency spikes and system instability under memory pressure -- by adding the following to /boot/loader.conf: hw.ena.enable_9k_mbufs="1" VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/12/ r360985 releng/12.1/ r361970 - ------------------------------------------------------------------------- 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-20:11.ena.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAl7fuERfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cITew/+MQpJIKHrlWjqcR9fvAeqR4rX3aBVNMkambeTa2nKY4/PH8XzVLnKvyuE O7ZtzaU3bz5xYkyYnlYSGstTRWk/BRCRgpZvzlPWVsvsFINgCHO5QsKHVyC0+/M2 Do3qRwxYDYPh0+Bz8QGuQGmpfMNpsuA//rfa12Ywp7jqu3IP8+0bBuWM71J7Bkyf WhEJIehFiU9iGUFS2LF7000CzIwmcTitCtYJFxxwaYYHGHT5nMtljcrsKK9I1N+Q f3mQ7dK8ryQ+H+CupfHodAYUeZyJbj/xVggdnzY45R1B9Tdr15VMPuurcqXyXIft Uj4UzdDUNgbUw4WQqfvqn8CDAT0V54NRhDs8AkYWn+GqaDDSnvcsKnI/V2UJgqTn Wp8ZClq7bF0mcBp7g1t97peseZsP+papJKsaVLKrTT+dw1x/aWz1cvK51x5UPWoW qaiFVMf5l9R0ZDcQxsyN/7gyHnZRR8X1wl1gVPVcJ8EEWs6Gh4sRTzXSDMDqsA/P 89hA6vPVeOmBqKM3BlR8MrDPIALjzxNvzu65NMLMcebyPudaY9a2GEd8acw6mwxh hQ015y9+MoMV8xD3gfjNLdQS7899eK1MwXu1UZPcUEOlYErAhjoGo51N4D6mfU62 7sDoy2Yt380Nmp57nUoanHkADzXPn8OV8fvlsTN6a0J4ZLu+KNM= =FDu4 -----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"