Bug 1973536
| Summary: | MTU got decrease 1 after removal of 802-3-ethernet configuration | ||||||||
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| Product: | Red Hat Enterprise Linux 8 | Reporter: | Gris Ge <fge> | ||||||
| Component: | NetworkManager | Assignee: | Beniamino Galvani <bgalvani> | ||||||
| Status: | CLOSED ERRATA | QA Contact: | Matej Berezny <mberezny> | ||||||
| Severity: | high | Docs Contact: | |||||||
| Priority: | high | ||||||||
| Version: | 8.4 | CC: | bgalvani, djasa, lrintel, mberezny, rkhan, sukulkar, till, vbenes | ||||||
| Target Milestone: | beta | Keywords: | Triaged | ||||||
| Target Release: | 8.6 | ||||||||
| Hardware: | x86_64 | ||||||||
| OS: | Linux | ||||||||
| Whiteboard: | |||||||||
| Fixed In Version: | NetworkManager-1.34.0-0.1.el8 | Doc Type: | No Doc Update | ||||||
| Doc Text: | Story Points: | --- | |||||||
| Clone Of: | Environment: | ||||||||
| Last Closed: | 2022-05-10 14:54:08 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: | |||||||||
| Attachments: |
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Created attachment 1791975 [details]
System logs with NM trace enabled
Hi Beniamino, Please take a quick a investigation to check whether this is bug is trivial or the tip of the iceberg. Thanks! Hi, this is the result of: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/commit/e23798a5e5e8d7eb615f0e8b305fc20b8b645c66 The problem is that NM stores (MTU - 1) as the initial MTU and then it resets the MTU to the stored value on deactivation. A fix is should be not too difficult. 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 (NetworkManager 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/RHEA-2022:1985 |
Created attachment 1791963 [details] Reproduce script Description of problem: When using `nmcli c mo br0 remove 802-3-ethernet` to remove MTU/etc settings, the MTU actually decreased 1. Version-Release number of selected component (if applicable): NetworkManager-1.30.0-7.el8 NetworkManager-1.32.0-0.5.el8 How reproducible: 100% Steps to Reproduce: 1. sudo ./mtu_bug.sh 2. 3. Actual results: The MTU of br0 changed to 1399 Expected results: The MTU of br0 revert back to default 1500. Additional info: