RAS Daemon

Those tools provide a way to get Platform Reliability, Availability and Serviceability (RAS) reports made via the Kernel tracing events.

The main repository for the rasdaemon is at:

• https://github.com/mchehab/rasdaemon

And two mirrors are available:

• https://gitlab.com/mchehab_kernel/rasdaemon
• http://git.infradead.org/users/mchehab/rasdaemon.git

Tarballs for each release can be found at:

• http://www.infradead.org/~mchehab/rasdaemon/

GOALS

Its initial goal is to replace the edac-tools that got bitroted after the addition of the HERM (Hardware Events Report Method )patches¹ at the EDAC Kernel drivers.

Its long term goal is to be the userspace tool that will collect all hardware error events reported by the Linux Kernel from several sources (EDAC, MCE, PCI, ...) into one common framework.

It is not meant to provide tools for doing error injection, as there are other tools already covering it, like: git://git.kernel.org/pub/scm/linux/kernel/git/gong.chen/mce-test.git

Yet, a few set of testing scripts are provided under /contrib dir.

When the final version of the HERM patches was merged upstream, it was decided to not expose the memory error counters to userspace. This is one of the differences from what it was provided by edac-utils, as EDAC 2.0.0 exports errors via a set of sysfs nodes that sums the amount of errors per DIMM, per memory channel and per memory controller. However, those counters are monotonically increased, and there's no way to detect if they're very sparsed in time, if the occurrence is increasing over time, or if they're due to some burst, perhaps due to a Solar Storm hitting the ionosphere.

In other words, the rationale for not exposing such the information is that:

1. can be easily accounted on userspace;
2. they're not really meaningful. E. g. one system with, let's say 10 corrected errors can be fine, while another one with the same amount of errors can have problems, as the error counters don't take into account things like system uptime, memory error bursts (that could be caused by a solar storm, for example), etc.

So, the idea since them was to make the kernel-userspace interface simpler and move the policy to the userspace daemon. It is up to the userspace daemon to correlate the data about the RAS events and provide the system administrator a comprehensive report, presenting him a better hint if he needs to contact the hardware vendor to replace a component that is working degraded, or to simply discard the error.

So, the approach taken here is to allow storing those errors on a SQLite database, in order to allow those data to be latter mining.

It is currently not part of the scope to do sophiscicated data mininy analysis, as that would require enough statistitical data about hardware MTBF. In other words, an abnormal component that needs to be replaced shoud be statistically compared with a similar component that operates under a normal condition. To do such checks, the analysis tool would need to know the probability density function(p. d. f.) of that component, and its rellevant parameters (like mean and standard derivation, if the p. d. f. funcion is a Normal distribution).

While this tool works since Kernel 3.5 (where HERM patches got added), in order to get the full benefit of this tool, Kernel 3.10 or upper is needed.

COMPILING AND INSTALLING

sqlite3 and autoconf needs to be installed. On Fedora, this is done by installing the following packages:

    make
    gcc
    autoconf
    automake
    libtool
    libtraceevent-devel
    tar
    sqlite-devel	(if sqlite3 will be used)
    perl-DBD-SQLite	(if sqlite3 will be used)

To install then on Fedora, run:

    $ dnf install -y make gcc autoconf automake libtool tar perl-dbd-sqlite \
      libtraceevent-devel

Or, if sqlite3 database will be used to store data:

    $ dnf install -y make gcc autoconf automake libtool tar sqlite-devel \
      libtraceevent-devel

There are currently 3 features that are enabled optionally, via ./configure parameters:

    --enable-sqlite3      enable storing data at SQL lite database (currently
			  experimental)
    --enable-aer            enable PCIe AER events (currently experimental)
    --enable-mce            enable MCE events (currently experimental)

In order to compile it, run:

    $ autoreconf -vfi
    $ ./configure [parameters]
    $ make

So, for example, to enable everything but sqlite3:

    $ autoreconf -vfi && ./configure --enable-aer --enable-mce && make

After compiling, run, as root:

    $ make install

RPM-based compilation

If the distribution is rpm-based, an alternative method would be to do:

    $ autoreconf -vfi && ./configure

The above procedure will generate a file at misc/rasdaemon.spec.

You may edit it, in order to add/remove the --enable-[option] parameters.

To generate the rpm files, do:

    # make mock

To install the rpm files, run, as root:

    # rpm -i $(ls SRPMS/rasdaemon-*.rpm|tail -1)

RUNNING

The daemon generally requires root permission, in order to read the needed debugfs trace nodes, with needs to be previously mounted. The rasdaemon will check at /proc/mounts where the debugfs partition is mounted and use it while running.

To run the rasdaemon in background, just call it without any parameters:

    # rasdaemon

The output will be available via syslog. Or, to run it in foreground and see the logs in console, run it as:

    # rasdaemon -f

or, if you also want to record errors at the database (--enable-sqlite3 is required):

    # rasdaemon -f -r

To post-process and decode received MCA errors on AMD SMCA systems, run:

	# rasdaemon -p --status <STATUS_reg> --ipid <IPID_reg> --smca --family <CPU Family> --model <CPU Model> --bank <BANK_NUM>

Status and IPID Register values (in hex) are mandatory. The smca flag with family and model are required if not decoding locally. Bank parameter is optional.

You may also start it via systemd:

    # systemctl start rasdaemon

The rasdaemon will then output the messages to journald.

TESTING

A script is provided under /contrib, in order to test the daemon EDAC handler. While the daemon is running, just run:

# contrib/edac-fake-inject

The script requires a Kernel compiled with CONFIG_EDAC_DEBUG and a running EDAC driver.

MCE error handling can use the MCE inject: https://git.kernel.org/pub/scm/utils/cpu/mce/mce-inject.git

For it to work, Kernel mce-inject module should be compiled and loaded.

APEI error injection can use this tool: https://git.kernel.org/pub/scm/linux/kernel/git/gong.chen/mce-test.git/

AER error injection can use this tool: https://git.kernel.org/pub/scm/linux/kernel/git/gong.chen/aer-inject.git/

SUBMITTING PATCHES

If you want to help improving this tool, be my guest! We try to follow the Kernel's CodingStyle and submission rules as a reference.

Before submitting your patch, please check the coding style with: scripts/checkpatch.pl.

In order to contribute with rasdaemon, please send a Merge Request via github repository at:

• https://github.com/mchehab/rasdaemon

Or, alternatively, send a pull request against gitlab repository at:

• https://gitlab.com/mchehab_kernel/rasdaemon

It is also recommended to send patches to [email protected] with a copy to:

• Mauro Carvalho Chehab <[email protected]>

Please notice that github is the preferred way. If you're not using it, please be kind enough to add an issue there for us to track the patch series.

Don't foget to add a description of the patch in the body of the email, adding a Signed-off-by: at the end of the patch description (before the unified diff with the patch).

We use Signed-off-by the same way as in kernel, so I'm transcribing bellow the same text as found under Kernel's Documentation/SubmittingPatches:

   "To improve tracking of who did what, especially with patches that can
    percolate to their final resting place in the kernel through several
    layers of maintainers, we've introduced a "sign-off" procedure on
    patches that are being emailed around.

    The sign-off is a simple line at the end of the explanation for the
    patch, which certifies that you wrote it or otherwise have the right to
    pass it on as an open-source patch.  The rules are pretty simple: if you
    can certify the below:

	    Developer's Certificate of Origin 1.1

	    By making a contribution to this project, I certify that:

	    (a) The contribution was created in whole or in part by me and I
		have the right to submit it under the open source license
		indicated in the file; or

	    (b) The contribution is based upon previous work that, to the best
		of my knowledge, is covered under an appropriate open source
		license and I have the right under that license to submit that
		work with modifications, whether created in whole or in part
		by me, under the same open source license (unless I am
		permitted to submit under a different license), as indicated
		in the file; or

	    (c) The contribution was provided directly to me by some other
		person who certified (a), (b) or (c) and I have not modified
		it.

	    (d) I understand and agree that this project and the contribution
		are public and that a record of the contribution (including all
		personal information I submit with it, including my sign-off) is
		maintained indefinitely and may be redistributed consistent with
		this project or the open source license(s) involved.

    then you just add a line saying

	    Signed-off-by: Random J Developer <[email protected]>

    using your real name (sorry, no pseudonyms or anonymous contributions.)"

Footnotes

1. http://lkml.indiana.edu/hypermail/linux/kernel/1205.1/02075.html ↩