Bug 216068 – [GLIB] kill-old-processes: Remove stale Apache2 shm segments

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[Diego Pino]

kill-old-processes: Remove stale Apache shm segments

[Diego Pino]

Created attachment 407742 [details]
Patch

[Diego Pino]

This issue was happening in several EWS workers running in the UAT. For instance:

https://ews-build.webkit-uat.org/#/builders/34/builds/4926/steps/10/logs/stdio

Apache2 doesn't start because it believes there's already an Apache2 instance running, when actually what's happening is that there's an orphan shm segment which pid matches the pid of the new Apache2 instance. In that case layout-test-results/error-log shows an error like this:

[Sat Aug 29 20:02:16.013912 2020] [core:crit] [pid 26] (17)File exists: AH00001: unable to create or access scoreboard "/tmp/WebKit/httpd.scoreboard" (name-based shared memory failure)

And here's a post with the description of the problem and solution:
https://makandracards.com/fabio-silva/49967-apache-unable-to-create-scoreboard-shared-memory-failure

[Diego Pino]

Created attachment 407744 [details]
Patch

[Alexey Proskuryakov]

Comment on attachment 407744 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=407744&action=review

> Tools/BuildSlaveSupport/kill-old-processes:27
> +import subprocess as sp

Why rename the module? WebKit coding style is to avoid abbreviations.

[Diego Pino]

Created attachment 407812 [details]
Patch

[Diego Pino]

(In reply to Alexey Proskuryakov from comment #4)
> Comment on attachment 407744 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=407744&action=review
> 
> > Tools/BuildSlaveSupport/kill-old-processes:27
> > +import subprocess as sp
> 
> Why rename the module? WebKit coding style is to avoid abbreviations.

Sorry, I didn't know about this code convention. I pushed a new patch undoing the renaming.

[EWS]

Committed r266507: <https://trac.webkit.org/changeset/266507>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 407812 [details].

[Radar WebKit Bug Importer]

<rdar://problem/68262415>

[Truitt Savell]

It looks like the changes in https://trac.webkit.org/changeset/266507/webkit 

broke our JSC EWS bot:
https://ews-build.webkit.org/#/builders/38/builds/1408

We will need to roll this out unless it can be fixed very quickly.


Traceback (most recent call last):
  File "Tools/BuildSlaveSupport/kill-old-processes", line 192, in <module>
    sys.exit(main(user))
  File "Tools/BuildSlaveSupport/kill-old-processes", line 184, in main
    removeOrphanShmSegmentsOf("apache2")
  File "Tools/BuildSlaveSupport/kill-old-processes", line 39, in removeOrphanShmSegmentsOf
    pid = futurePidOf(task)
  File "Tools/BuildSlaveSupport/kill-old-processes", line 56, in futurePidOf
    ps = subprocess.Popen(task, stderr=subprocess.STDOUT, stdout=devnull)
  File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1047, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

[WebKit Commit Bot]

Re-opened since this is blocked by bug 216135

[Diego Pino]

Created attachment 407941 [details]
Patch

[Lauro Moura]

Created attachment 408266 [details]
Refactored patch.

[EWS]

ChangeLog entry in Tools/ChangeLog is not at the top of the file.

[Lauro Moura]

Created attachment 408309 [details]
Patch for landing

[EWS]

Committed r266775: <https://trac.webkit.org/changeset/266775>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 408309 [details].