Bug 2148578
| Summary: | Hit message: couldn't write '1' to 'vm/unprivileged_userfaultfd in the package installation terminal | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 8 | Reporter: | chhu |
| Component: | libvirt | Assignee: | Jiri Denemark <jdenemar> |
| Status: | CLOSED ERRATA | QA Contact: | yalzhang <yalzhang> |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 8.7 | CC: | hasuzuki, jdenemar, jsuchane, jtomko, lmen, lnykryn, msekleta, systemd-maint-list, virt-maint |
| Target Milestone: | rc | Keywords: | Triaged |
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | libvirt-8.0.0-14.module+el8.8.0+17806+11a519fc | Doc Type: | If docs needed, set a value |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2023-05-16 08:18:36 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 2158160 | ||
| Bug Blocks: | |||
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Description
chhu
2022-11-26 02:40:23 UTC
It seems that we don't have unprivileged_userfaultfd in RHEL8, so either libvirt needs to drop it from their sysctl conf or this bug should be reassigned to kernel to backport it. This is the patch for the kernel: https://lore.kernel.org/all/20190319030722.12441-1-peterx@redhat.com/ Well, the problem is not missing vm/unprivileged_userfaultfd because the
postcopy-migration.sysctl file contains
-vm.unprivileged_userfaultfd = 1
In other words, we explicitly request write failures to be ignored. However
systemd still logs the error. Logging it is fine, after all, the log message
has an info (or notice, I don't remember now) level so it's ok. But the
question is whether printing it on stderr makes sense.
Anyway, this is not a bug from libvirt POV as we mark the settings with "-".
We could remove the file completely from RHEL-8, but it seems keeping it and
marking as "ignore failures" is more future proof as there would be nothing to
worry about should the parameter be backported to RHEL-8.
If you think this is not an issue from systemd POV, please explain it and
close the bug.
Looks like RHEL8 libvirt is missing the change that ignored the failures:
commit 558f00397a0d46ad22bf53a22a40ed6fc4fdb5eb
qemu: Ignore missing vm.unprivileged_userfaultfd sysctl
git describe: v8.0.0-328-g558f00397a contains: v8.1.0~154
Heh. I wonder how this happened. I thought I was adding the "-" prefix specifically because of RHEL-8 :-( Anyway, this clearly is libvirt bug then. However, would the dash actually help with systemd (as it is ignoring failures even without it)? There is a bug in systemd-sysctl on RHEL-8, we print the error message even in the case when option name is prefixed with "-". This is inconsistent with the current upstream behavior which was changed in, https://github.com/systemd/systemd/commit/32458cc9687c1b60ff0f22c0e71da93ce78b1534 . As for ignoring failures, recently there has been a strict mode (sysctl exits with error if write wasn't successful) introduced for systemd-sysctl in https://github.com/systemd/systemd/commit/e88748c17e58aad6818e64fd3071de011808165e . However, it is not used by default and we wouldn't be able to used it by default as well. (In reply to Michal Sekletar from comment #6) > There is a bug in systemd-sysctl on RHEL-8, we print the error message even > in the case when option name is prefixed with "-". I have now filled https://bugzilla.redhat.com/show_bug.cgi?id=2158160. Reproduce the bug on libvirt-8.0.0-13 with systemd-239-69.el8.x86_64: 1. install the libvirt related packages; 2. remove libvirt-daemon-driver-qemu package: # rpm -e libvirt-daemon-driver-qemu libvirt-daemon-kvm libguestfs 3. download the package, and install by rpm: # rpm -ivh libvirt-daemon-driver-qemu-8.0.0-13.module+el8.8.0+17719+f18c2d1b.x86_64.rpm Verifying... ################################# [100%] Preparing... ################################# [100%] Updating / installing... 1:libvirt-daemon-driver-qemu-8.0.0-################################# [100%] Couldn't write '1' to 'vm/unprivileged_userfaultfd', ignoring: No such file or directory Test on libvirt-8.0.0-14 with systemd-239-69.el8.x86_64: 1. install all libvirt related packages; 2. remove libvirt-daemon-driver-qemu package: # rpm -e libvirt-daemon-driver-qemu libvirt-daemon-kvm libvirt 3. install libvirt-daemon-driver-qemu by rpm: # rpm -ivh libvirt-daemon-driver-qemu-8.0.0-14.module+el8.8.0+17806+11a519fc.x86_64.rpm Verifying... ################################# [100%] Preparing... ################################# [100%] Updating / installing... 1:libvirt-daemon-driver-qemu-8.0.0-################################# [100%] Couldn't write '1' to 'vm/unprivileged_userfaultfd', ignoring: No such file or directory It fails because the systemd bug is not fixed. I will retest it after bug 2158160 fixed. Test on libvirt-8.0.0-14.module+el8.8.0 with systemd-239-70.el8, the result is as expected: 1. install all libvirt related packages; 2. remove libvirt-daemon-driver-qemu; # rpm -e libvirt-daemon-driver-qemu libvirt-daemon-kvm libvirt libguestfs 3. install libvirt-daemon-driver-qemu by rpm command: # rpm -ivh ./libvirt-daemon-driver-qemu-8.0.0-14.module+el8.8.0+17806+11a519fc.x86_64.rpm Verifying... ################################# [100%] Preparing... ################################# [100%] Updating / installing... 1:libvirt-daemon-driver-qemu-8.0.0-################################# [100%] no error occurs, the issue is fixed. 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: virt:rhel and virt-devel:rhel 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-2023:2757 |