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Description of problem: The kernel doesn't seem to synchronize the RTC to the system clock reliably. It should normally set the RTC about every 11 minutes, but it may take a very long time (hours, days, or possibly never) for the update to actually happen. The problem seems to be in inaccurate scheduling of the update. This was observed with upstream kernels and also RHEL kernels. An upstream report: https://lkml.org/lkml/2019/11/27/263 Version-Release number of selected component (if applicable): kernel-4.18.0-167.el8.x86_64 How reproducible: Often, but not always. Steps to Reproduce: 1. start chronyd with rtcsync in chrony.conf (that is the default) 2. chronyc waitsync 3. hwclock --set --date '10 sec' 4. wait >11 minutes 5. run timedatectl and compare "Local time" with "RTC time" Actual results: RTC time off by about 10 seconds Expected results: RTC time within <1 second of the Local time Additional info:
After some discussion, a different fix was prepared (using a hrtimer) and is waiting to be merged: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=c9e6189fb03123a7dfb93589280347b46f30b161
The following Merge Request has pipeline job artifacts available: Title: [RHEL8.5] Fix RTC synchronization MR: https://gitlab.com/redhat/rhel/src/kernel/rhel-8/-/merge_requests/158 Pipeline: https://gitlab.com/redhat/rhel/src/kernel/rhel-8/-/pipelines/269596926 This Repo URL is *not* accessible from a web browser! It only functions as a dnf or yum baseurl. Repo URL: https://s3.upshift.redhat.com/DH-PROD-CKI/internal/269596973/$basearch/4.18.0-296.el8.test.$basearch 4.18.0-296.el8.test.s390x: Job: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420022 Gitlab browser: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420022/artifacts/browse/artifacts/repo/4.18.0-296.el8.test.s390x/ Current automated test status: success 4.18.0-296.el8.test.ppc64le: Job: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420019 Gitlab browser: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420019/artifacts/browse/artifacts/repo/4.18.0-296.el8.test.ppc64le/ Current automated test status: success 4.18.0-296.el8.test.aarch64: Job: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420018 Gitlab browser: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420018/artifacts/browse/artifacts/repo/4.18.0-296.el8.test.aarch64/ Current automated test status: success 4.18.0-296.el8.test.x86_64: Job: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420017 Gitlab browser: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/1093420017/artifacts/browse/artifacts/repo/4.18.0-296.el8.test.x86_64/ Current automated test status: success
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: kernel security, bug fix, and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:4356