psgi_plugin.so: undefined symbol: boot_DynaLoader

[Janne Snabb]

Impact:
It appears that uwsgi-plugin-psgi does not load libperl.so and therefore the package is unusable.

Fix: the psgi plugin uses LDFLAGS to link with libraries so they are ordered wrong on the command line (due to ld --as-needed) so it ends up not linking against them at all.
the fix is to add the libraries to LIBS
The same fix is applied in upstream and quantal.

TESTCASE:

1. # apt-get install uwsgi uwsgi-plugin-psgi

2. # vi /etc/uwsgi/apps-available/test.yaml
Put the following contents there:
---cut-here---
uwsgi:
  plugins: psgi
  psgi: /dev/null
---cut-here---

3. # ln -s /etc/uwsgi/apps-available/test.yaml /etc/uwsgi/apps-enabled/

4. # service uwsgi restart

5. # less /var/log/uwsgi/app/test.log
Observe the following error message: /usr/lib/uwsgi/plugins/psgi_plugin.so: undefined symbol: boot_DynaLoader

The problem is obvious when looking at the uwsgi plugin file with ldd:
$ ldd /usr/lib/uwsgi/plugins/psgi_plugin.so
 linux-vdso.so.1 => (0x00007fff395ff000)
 libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2f4a70d000)
 libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f2f4a4f0000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f2f4acfe000)

Compare the ldd output of the fixed plugin:
$ ldd /usr/lib/uwsgi/plugins/psgi_plugin.so
        linux-vdso.so.1 => (0x00007fffa33ff000)
        libperl.so.5.14 => /usr/lib/libperl.so.5.14 (0x00007fbf47482000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fbf47265000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fbf46ea7000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fbf46ca3000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fbf469a9000)
        libcrypt.so.1 => /lib/x86_64-linux-gnu/libcrypt.so.1 (0x00007fbf4676f000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fbf47a13000)

Regression potential:
only a change in the linking of a single plugin and the plugin is unusable without the fix
low risk of regressions

rest of original report:
It does not load the perl shared library!

As a workaround I retrieved the current source package version 1.2.3+dfsg-2~experimental1 from Debian and built it on Ubuntu precise. It works fine (and gives excellent PSGI performance :).

The working version of the plugin depends on libperl.so while the non-working version does not.

I think the problem has been fixed by this upstream commit:
https://github.com/unbit/uwsgi/commit/15aaddb4d306912c2cb570cb47a82a68b900a27a

See the changes in plugins/psgi/uwsgiplugin.py

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: uwsgi-plugin-psgi 1.0.3+dfsg-1
ProcVersionSignature: Ubuntu 3.2.0-25.40-generic 3.2.18
Uname: Linux 3.2.0-25-generic x86_64
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
Date: Sat Jul 14 01:57:46 2012
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110920.2)
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: uwsgi
UpgradeStatus: Upgraded to precise on 2012-04-27 (77 days ago)

[Julian Taylor (jtaylor)]

the issue seems fixed in quantals 1.2.3+dfsg-1 too

[Julian Taylor (jtaylor)]

thanks for the report and link to the patch.

I have uploaded a fixed package to -proposed
please test it when it has been accepted.

[Adam Conrad (adconrad)]

Hello Janne, or anyone else affected,

Accepted uwsgi into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/uwsgi/1.0.3+dfsg-1ubuntu0.1 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 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 change the bug tag from verification-needed to verification-done. If it does not, change the tag to verification-failed. 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!

[Janne Snabb (snabb)]

Hi,

I installed 1.0.3+dfsg-1ubuntu0.1 from precise-proposed and looks like it is working fine.

My PSGI app was loaded successfully:

Tue Jul 17 08:12:13 2012 - PSGI app 0 (/www/test/TestApp/bin/app.pl) loaded at 0x176d038

And nginx can successfully request a page from it:

[pid: 28119|app: -1|req: -1/1] 124.248.XXX.XXX () {44 vars in 679 bytes} [Tue Jul 17 08:13:19 2012] GET / => generated 5373 bytes in 139 msecs (HTTP/1.0 200) 4 headers in 143 bytes (0 switches on core 0)

Thank you!

[Janne Snabb (snabb)]

I forgot to add a successfull test case result which matches the original simple test case.

The test case in the bug description can be now verified by observing the following in /var/log/uwsgi/app/test.log:

Tue Jul 17 22:06:05 2012 - PSGI app 0 (/dev/null) loaded at 0x105ed18
Tue Jul 17 22:06:05 2012 - *** uWSGI is running in multiple interpreter mode ***
Tue Jul 17 22:06:05 2012 - spawned uWSGI master process (pid: 6590)
Tue Jul 17 22:06:05 2012 - spawned uWSGI worker 1 (pid: 6592, cores: 1)
Tue Jul 17 22:06:05 2012 - spawned uWSGI worker 2 (pid: 6593, cores: 1)

We can see that the PSGI now starts successfully (our test app "/dev/null" is not very useful though :).

[Launchpad Janitor (janitor)]

This bug was fixed in the package uwsgi - 1.0.3+dfsg-1ubuntu0.1

---------------
uwsgi (1.0.3+dfsg-1ubuntu0.1) precise-proposed; urgency=low

  * psgi-link-fix.patch:
    fix linking of psgi plugin with the perl libraries (LP: #1024528)
 -- Julian Taylor <email address hidden> Sat, 14 Jul 2012 18:21:33 +0200