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rseq in glibc coming to CentOS Stream 9
by Florian Weimer 19 Jan '22

19 Jan '22

The only way to implement sched_getcpu efficiently on AArch64 is to use rseq and the per-thread CPU field in the rseq area. Unlike other architectures, there is no vDSO acceleration for sched_getcpu or getcpu on AArch64, and there does not seem to be a special register available that could be used for this. (E.g., on x86-64, the kernel uses otherwise-unused segment limits; access is not particularly fast, but at least there is no system call involved.) No application changes are needed to benefit from this optimization, and even architectures with existing vDSO acceleration benefit (slightly). Upstream glibc will enable rseq in the upcoming 2.35 release, and while we are not putting that glibc version into CentOS anytime soon, we have backported the rseq acceleration for sched_getcpu to CentOS Stream 9, glibc-2.34-19.el9 to be precise: glibc: Optional sched_getcpu acceleration using rseq <https://bugzilla.redhat.com/show_bug.cgi?id=2024347> However, Fedora rawhide testing revealed an integration issue with CRIU: Implement rseq support, as required by glibc 2.35 <https://github.com/checkpoint-restore/criu/issues/1696> criu: Implement rseq support <https://bugzilla.redhat.com/show_bug.cgi?id=2033397> Therefore, we currently do not enable rseq acceleration by default, but we plan to do so in the future, once CRIU fixes are available in relevant places. Therefore, applications need to be launched with the GLIBC_TUNABLES=glibc.pthread.rseq=1 environment variable for the time being to benefit from rseq-based sched_getcpu acceleration. This time, no bad seccomp interactions are expected because we leaned on browsers a while back to fix their sandboxes. Container engines should not be impacted because the glibc integration treats an initial EPERM failure of the rseq system call as an indicator that rseq is not available. (Only success for the first rseq system call followed by failure for rseq system calls on newly created threads is problematic; this part needed fixing in browser sandboxes.) A few applications which currently use rseq will need integration with the new glibc way of doing things if they want to keep benefiting from rseq. Mathieu Desnoyers is enhancing librseq; direct consumers such as tcmalloc will need to be updated separately. I do not know yet how the interaction between CentOS Stream 9 glibc and these applications will look like because we have not backported the public rseq symbols that glibc is adding in glibc 2.35 (__rseq_offset, __rseq_size, __rseq_flags). The current downstream glibc default (without GLIBC_TUNABLES=glibc.pthread.rseq=1) is not to use rseq at all, leaving it available for application use, so we have some time to figure out the details. Thanks, Florian

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Board office hours
by Shaun McCance 18 Jan '22

18 Jan '22

Last week was a board meeting, so this week we'll have board office hours. Join the board tomorrow, January 19, at 15:00 UTC. https://meet.google.com/atj-vfsm-emk If you need dial-in details instead, just email me off-list. Thanks, Shaun

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FOSDEM Dojo, February 3-4
by Shaun McCance 18 Jan '22

18 Jan '22

I've just published the schedule for the FOSDEM Dojo. Like FOSDEM, the Dojo will again be virtual this year. Registration is free, but please do register. See the wiki for details. https://wiki.centos.org/Events/Dojo/FOSDEM2022 Thanks, Shaun

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Re: [CentOS-devel] [CentOS-announce] CESA-2022:0063 Moderate CentOS 7 kernel Security Update
by Chris Schanzle 18 Jan '22

18 Jan '22

Hi Johnny, It looks like this kernel update did not land in the right directories on the servers. I found them in https://mirror.interserver.net/centos/7/updates/ instead of https://mirror.interserver.net/centos/7/updates/x86_64/Packages/ And thus, are not found by yum. As always, thank you for your efforts! On 1/18/22 8:57 AM, Johnny Hughes wrote: > CentOS Errata and Security Advisory 2022:0063 Moderate > > Upstream details at : https://gcc02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faccess.re… > > The following updated files have been uploaded and are currently > syncing to the mirrors: ( sha256sum Filename ) > > > Source: > 0ccd3b419ddb59738ad345ec66203a38f2d42df2f1fb1051807145f2459dbf91 kernel-3.10.0-1160.53.1.el7.src.rpm > > >

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Welcome to Shaun McCance, our new community manager
by Rich Bowen 16 Jan '22

16 Jan '22

As many of you are aware, I have been serving as the Community Manager for the CentOS project for the past 3 years, having been appointed to this position by the Board in the April 2018 board meeting. Over the coming weeks, I will be moving to a different position (still within the Open Source Programs Office at Red Hat, but doing something different) and Shaun McCance will be moving into this role. Shaun has extensive experience in open source projects, including decades with the Gnome Foundation. He works for the Red Hat OSPO, and is based in Ohio, USA. The past 3 years have been challenging, interesting, difficult, and rewarding. And although the past year has been very, very hard, I am very proud of what we have accomplished together as a community: * Community-nominated board (see my next email for more about this!) * Public/Open board meetings * New SIGs! (Automotive, Infrastructure, kmods, Hyperscale, Feature Request) * Contribution path via CentOS Stream * Code of conduct * etc So, thank you all for your support and encouragement over the past 3 years, and for participating in all of the above initiatives and so much more. And please welcome Shaun, and give him just as much (or more!) encouragement as he takes on this important role and helps guide the community. --Rich

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Welcome to our new Board members!
by Rich Bowen 14 Jan '22

14 Jan '22

It is my enormous pleasure to introduce our two new board members, elected by the sitting board at yesterday's Board meeting. (Full minutes coming in a day or two.) Amy Marrich Celeste Lyn Paul I will allow them to introduce themselves more thoroughly over the coming days, but please do join me in welcoming them to our board! As you are already aware, Jim Perrin and Karanbir Singh both have stepped down from the board at the end of the most recent term, after many years of service, and we thank them for all of their hard work over the past 17 years. --Rich

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Possible openssl-1.0.2k-23.el7_9 issue
by Johnny Hughes 14 Jan '22

14 Jan '22

I am working to release an update set for CentOS Linux 7, it contains openssl-1.0.2k-23.el7_9, which has this bug reported: https://bugzilla.redhat.com/show_bug.cgi?id=2039993 There is also this article: https://access.redhat.com/solutions/6637201 (requires an access.redhat.com subscription) The current update set is currently in QA testing. It may fail and not be able to be released .. in which case we wouuld remove openssl and try again to get it to pass tests. I just wanted to get this out there in case anyone has issues. Thanks, Johnny Hughes

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Is there a feeds.centos.org for CentOS 9 Stream?
by Steven Rosenberg 14 Jan '22

14 Jan '22

Is there something equivalent to https://feeds.centos.org that does the same thing for CentOS 9 Stream?

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CentOS Hyperscale SIG Quarterly Report for 2021Q4
by Davide Cavalca 10 Jan '22

10 Jan '22

Hello, I've published our quarterly update for the Hyperscale SIG activities on the CentOS Blog: https://blog.centos.org/2022/01/centos-hyperscale-sig-quarterly-report-for-… Cheers Davide

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[REPORT] Automotive SIG
by Jeffrey Osier-Mixon 10 Jan '22

10 Jan '22

January 2022 Quarterly report submitted by: Jefro Osier-Mixon, Red Hat - acting chair _____________________________________ Membership update (members added, removed. Chair changes.) This SIG does not have a formal membership process. The mailing list currently has 77 subscribers representing at least yy companies. I have been asked to act as chair for the first few months in order to stabilize the SIG. _____________________________________ Releases in the most recent quarter (or most recent release, if none in that quarter) The SIG is not yet creating builds or publishing releases, but we are very close to doing so at this point; see the report below. _____________________________________ Health report and general activity narrative. The SIG has had two public meetings per month, one formal and one informal "office hours", each with 25-40 attendees representing 7-10 separate organizations. We feel this is a good start at corporate community diversity but will continue to work toward a community-driven project. This SIG is intended to be a community effort with contributions and shared benefits from all participants. Several RH employees made the first contribution to the project as well as the infrastructure required to build and test it. We now occupy a gitlab repository building software regularly, with build instructions provided, and we are on track for a downloadable release in Q1 2022. This is a high-level summary of current activity from our technical lead: - The work keeps on going at: https://gitlab.com/redhat/automotive/automotive-sig - We have created manifests in that repository that can be used with OSBuild to create a number of images. - We currently support: - qemu and raspberry pi - x86_64 and aarch64, - ostree-based (default) and non-ostree-based - booting via uefi of by-passing it and booting directly the kernel - We then have 3 images - minimal - osbuilder (containing the tools allowing to build images with osbuild) - neptune (demo image with a graphical interface running the demo app: neptune) - The OSBuild manifests have been streamed-line and simplified a lot. If you have not look at them in a while have a look ! - We have also added a mechanism to easily build images from within a virtual machine, which makes it easier to build images without root privileges. - The VM created for the step just above (^) can also be migrated to a different system, thus allowing to build more easily in a different architecture. - Instructions on how to build images have also been greatly simplified The doc at: https://sigs.centos.org/automotive/building/ is up to date - We have a kernel-auto package based on the CentOS-Stream package and with the Real-Time patches included - We have a few koji tags set-up for the SIG, the kernel-auto is the main beneficiary of them (with a couple of other RT related packages) - We are working on automatically building some of our sample images and making them available. A few of them can be found at: https://pingou.fedorapeople.org/images/ but this is a temporary location and they are now over a month old. - We have been sending weekly updates to the SIG mailing list on a regular cadence and will try to continue doing it. _____________________________________ Issues for the board to address, if any None, keep up the excellent work :) Jeffrey "Jefro" Osier-Mixon | jefro(a)redhat.com Red Hat Office of the CTO | Sr. Principal Community Architect, Automotive

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