[UBUNTU 20.04] smc: SMC connections hang with later-level implementations
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Ubuntu on IBM z Systems |
Fix Released
|
Undecided
|
Skipper Bug Screeners | ||
linux (Ubuntu) |
Fix Released
|
Medium
|
Frank Heimes | ||
Focal |
Fix Released
|
Medium
|
Frank Heimes | ||
Groovy |
Fix Released
|
Medium
|
Frank Heimes |
Bug Description
SRU Justification:
==================
[Impact]
* Connections from later-level SMC (protocol) versions to an SMC-enabled server on Linux hang.
* Later-level versions of SMC (although backwards-
* The solution to avoid such hangs is to introduce toleration for later version numbers, and support CLC messages of arbitrary length.
[Fix]
* fb4f79264c0fc6f
[Test Case]
* Requires two IBM z13/z13s GA2 or LinuxONE Rockhopper/Emperor systems with RoCE Express adapter v2(.1) for SMC-D usage.
* One system needs to run the initial SMC-D version, the other a newer version.
* Establish a connection between both system and monitor/verify if it's reliable or if it hangs.
[Regression Potential]
* The regression can be considered as medium to low:
* Since SMC-D is a pretty special way of doing shared memory communications and not that wide-spread.
* However, the code that is changed is common code.
* But the patch is straight forward and only modifies /net/smc/smc_clc.c and /net/smc/smc_clc.h
* It largely bumps limits (allows larger messages), adds a check and introduces toleration, rather than changing control or flow.
[Other]
* The above fix is currently in 'linux-next' and tagged with next-20200709.
* It is still assumed that it gets accepted for 5.8.
* However, since this is not guaranteed this SRU request is for focal and groovy - to make sure that no potential regressions are introduced in case the patch will not end up in 5.8.
__________
Description: smc: SMC connections hang with later-level implementations
Symptom: Connections from later-level SMC versions to an SMC-enabled
Problem: Later-level versions of SMC present, although backwards-
Solution: Adjust for tolerating later version numbers, and support CLC
Reproduction: Enable a server on Linux for SMC, and connect using a later-
Applicable for: Ubuntu 20.04
affects: | linux (Ubuntu) → smc-tools (Ubuntu) |
affects: | smc-tools (Ubuntu) → linux (Ubuntu) |
information type: | Public → Private |
information type: | Private → Public |
Changed in ubuntu-z-systems: | |
status: | Incomplete → Triaged |
Changed in linux (Ubuntu Groovy): | |
status: | New → Triaged |
Changed in linux (Ubuntu Focal): | |
status: | New → Triaged |
assignee: | nobody → Frank Heimes (fheimes) |
Changed in linux (Ubuntu Groovy): | |
assignee: | nobody → Frank Heimes (fheimes) |
Changed in linux (Ubuntu Groovy): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Focal): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Focal): | |
status: | In Progress → Fix Committed |
Changed in ubuntu-z-systems: | |
status: | Fix Committed → Fix Released |
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