menu-cached process is using 100% CPU

[William G. Comnisky]

[Impact]

Without this bugfix, users who resume from suspend will be greeted with a heavy CPU load when they resume. This is especially bad for older computers who may not be able to hand a large CPU load, and menu-cache is included by default in Lubuntu, where this is especially important.

[Test Case]

1. Suspend your computer with the menu-cache process running.
2. Resume from suspend.
3. Try to press Alt + F2 or use any other program which calls menu-cached.

It should work as normal, but it uses up a lot of CPU power.

[Regression Potential]

This bugfix cherry picks an upstream commit that hasn't been tagged yet. As such, there might be additional improvements before it is released.

Also, this modifies how processes are handled; specifically, it terminates any processes which return a socket error. This could eventually bitrot and result in processes returning valid values but it really shows as an error.

While all of those are theoretical, it is definitely a possibility. Other than those two considerations, the regression risk is low.

[Original Description]

Hey all,

I don't know you guys are looking for the issues opened on Github (https://github.com/lxde/menu-cache/issues/) - currently there are 5 reported there, but I'd like to report specifically for the menu-cached process using 100% of CPU (we also have an issue opened on Github for this with lots of comments: https://github.com/lxde/menu-cache/issues/7).

I'm using a brand new installation of Lubuntu 16.10 in my laptop.

I noticed the machine temperature was too hot (96 degrees!!!) so I took a look on top and the menu-cached was the guilty. I killed it and everything was as usual again.

I just don't know if it was because I returned from the suspended mode or if it's because I tried to run a custom command with "Open With". I did both in sequence/same session.

$ dpkg -l |grep -iP "menu.*?cache"
ii libmenu-cache-bin 1.0.1-1build1 amd64
ii libmenu-cache3:amd64 1.0.1-1build1 amd64

Thanks

[Launchpad Janitor (janitor)]

This bug was fixed in the package menu-cache - 1.0.2-1

---------------
menu-cache (1.0.2-1) unstable; urgency=medium

  * Merging upstream version 1.0.2 (LP: #1635438).
  * Bump Standards-Version to 3.9.8.

 -- Andriy Grytsenko <email address hidden> Sun, 06 Nov 2016 19:17:53 +0200

[Simon Quigley (tsimonq2)]

Actually, this bug wasn't completely fixed. See the upstream issue for more details, but I'm converting this into a 0 day SRU bug for Artful, and once it's there, an SRU bug for all other supported releases of Lubuntu.

[Andy Whitcroft (apw)]

Hello William, or anyone else affected,

Accepted menu-cache into artful-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/menu-cache/1.0.2-3ubuntu0.17.10.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-artful to verification-done-artful. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-artful. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Simon Quigley (tsimonq2)]

This update works as intended on my system, it fixes the problem correctly.

[William G. Comnisky (w-comnisky)]

Hey guys,

I'm glad to hear that you managed to reproduce and fix it.

Thanks for that

[Launchpad Janitor (janitor)]

This bug was fixed in the package menu-cache - 1.0.2-3ubuntu0.17.10.1

---------------
menu-cache (1.0.2-3ubuntu0.17.10.1) artful; urgency=high

  * Fix menu-cached so 100% CPU isn't used after suspend (LP: #1635438).
    - 90-1-fix-100-cpu-load.patch
    - 90-2-fix-100-cpu-load.patch

 -- Simon Quigley <email address hidden> Wed, 18 Oct 2017 18:47:37 -0500

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for menu-cache has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Simon Quigley (tsimonq2)]

Zesty is EOL, but I'll look into seeing if this is a Xenial problem as well ASAP.

Thanks.

[Chris J Arges (arges)]

Hello William, or anyone else affected,

Accepted menu-cache into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/menu-cache/1.0.1-1ubuntu0.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Simon Quigley (tsimonq2)]

After updating to 1.0.1-1ubuntu0.2 from xenial-proposed, the problem is indeed fixed.

Thanks.

[Launchpad Janitor (janitor)]

This bug was fixed in the package menu-cache - 1.0.1-1ubuntu0.2

---------------
menu-cache (1.0.1-1ubuntu0.2) xenial; urgency=high

  * Fix menu-cached so 100% CPU isn't used after suspend (LP: #1635438).
    - 90-1-fix-100-cpu-load.patch
    - 90-2-fix-100-cpu-load.patch

 -- Simon Quigley <email address hidden> Sun, 28 Jan 2018 23:15:59 -0600