550966 - 'Deep recursion on subroutine' if there are compilation errors in the extension code.

Status: RESOLVED FIXED

(Bugzilla :: Extensions, defect)

Description

[Tiago Mello [:timello]]

If an extension is deployed with compilation errors, it breaks the webserver consuming a lot of CPU.

It is quite dangerous, if the extension is deployed in a production server and it contains compilation errors.

Also, it turns the debug harder.

We should avoid this recursion somehow.

Here are the apache logs:

[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Install::Util::extension_requirement_packages" at Bugzilla/Install/Util.pm line 393.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::template" at Bugzilla/Error.pm line 91.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Template::create" at Bugzilla.pm line 179.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Template::_include_path" at Bugzilla/Template.pm line 795.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::extensions" at Bugzilla/Install/Util.pm line 156.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Extension::load_all" at Bugzilla.pm line 200.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Extension::load" at Bugzilla/Extension.pm line 128.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Error::ThrowCodeError" at Bugzilla/Extension.pm line 67.
[Mon Mar  8 16:33:49 2010] admin.cgi: Deep recursion on subroutine "Bugzilla::Error::_throw_error" at Bugzilla/Error.pm line 144.

Comment 1

[Tiago Mello [:timello]]

Hey Max,

Any thought?

Comment 2

[Max Kanat-Alexander]

  There is code in the template hooks to prevent this. Are you sure you haven't modified that code?

Comment 3

[Michael Thomas (Mockodin)]

Tiago

Windows has this issue or similar under Mod_Perl, though as Max mentioned it was fixed. Can you provide detail for you server configs?

Comment 4

[Tiago Mello [:timello]]

Max, I haven't modified anything. It is the trunk code.
Michael, I'm running it on Ubuntu 9.10, in order to reproduce the error I can just add a 'use Foo::Bar;' which is an invalid package, that is, any code error can cause that recursion.

Comment 5

[Tiago Mello [:timello]]

Forgot to mention, the code error is in the extension, Extension.pm for instance.

Comment 6

[Tiago Mello [:timello]]

But, the recursion starts when I try to access the page which is 'calling' the hook directly. If I access any other page, it works.

Comment 7

[Max Kanat-Alexander]

  Hmm, okay. Do you have a Config.pm in your extension, or not? I can look into this.

Comment 8

[Tiago Mello [:timello]]

Hmm. Not sure why, but I found the real steps to reproduce:

1. Create an empty extension using './extensions/create.pl Test';
2. Edit the extensions/Test/Extension.pm and add any code error;
3. Try to access admin.cgi.

Then you get the recursion.

Comment 9

[Tiago Mello [:timello]]

The problem seems to be in admin.cgi

Comment 10

[Tiago Mello [:timello]]

Attachment: an example.

hmm.. it happens with any page.

Comment 11

[Tiago Mello [:timello]]

Sorry, for the spams, just posting my investigations.

Well, I can reproduce it on the Example extension. But, somehow, it works when I access page.cgi?id=example.html or index.cgi, but not for query.cgi, admin.cgi, report.cgi, show_bug.cgi, buglist.cgi...

Comment 12

[Max Kanat-Alexander]

Attachment: v1

Okay, this fixes it.

  The problem was that calling eval { Bugzilla->extensions } was somehow hiding the syntax error and then getting into a crazy infinite loop. So instead, I check if Bugzilla.pm is loaded, which is better anyway. (I don't do "require Bugzilla" because that would skip the extension_requirement_packages code during checksetup.pl if Bugzilla.pm could be loaded.)

Comment 13

[Max Kanat-Alexander]

Committing to: bzr+ssh://bzr.mozilla.org/bugzilla/trunk/
modified Bugzilla/Install/Util.pm
Committed revision 7060.

Committing to: bzr+ssh://bzr.mozilla.org/bugzilla/3.6/
modified Bugzilla/Install/Util.pm
Committed revision 7029.