-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

=============================================================================
FreeBSD-EN-20:12.iflib                                          Errata Notice
                                                          The FreeBSD Project

Topic:          iflib watchdog timeout resetting idle queues

Category:       core
Module:         kernel
Announced:      2020-06-09
Affects:        FreeBSD 12.1
Corrected:      2020-01-10 18:29:05 UTC (stable/12, 12.1-STABLE)
                2020-06-09 16:11:54 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

iflib is a framework that contains common code for network drivers to use,
reducing code duplication. One function it contains is a "watchdog" that
periodically checks the driver's software Tx queues to see if they're hung.

II.  Problem Description

The iflib watchdog would sometimes trigger a false positive queue hang just
after a link state change.

III. Impact

The iflib framework would print messages for the affected devices such as

"igb0: TX(2) desc avail = 1024, pidx = 0"

and would stop allowing Tx traffic to be sent.

IV.  Workaround

No workaround is available.  Systems that do not use iflib-based interfaces
are not vulnerable.

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.

# fetch https://security.FreeBSD.org/patches/EN-20:12/iflib.patch
# fetch https://security.FreeBSD.org/patches/EN-20:12/iflib.patch.asc
# gpg --verify iflib.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/12/                                                        r356605
releng/12.1/                                                      r361971
- -------------------------------------------------------------------------

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=239240>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-20:12.iflib.asc>
-----BEGIN PGP SIGNATURE-----
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=VqeW
-----END PGP SIGNATURE-----