Segmentation Fault

[fixedd]

Our script is dying with a Segmentation Fault in some cases (but not all). It seems to happen in executions of our script which cause a very high number (a few thousand) of messages to be delivered into our queue and it's 100% reproducable with those sets of data. I don't really know how to work with GDB, but I was able to get the following out of it:

0 zend_std_get_method (object_ptr=0x2959ac0, method_name=0x1f425e0 "connectionClose", method_len=15) at /build/buildd/php5-5.3.10/Zend/zend_object_handlers.c:847

847 /build/buildd/php5-5.3.10/Zend/zend_object_handlers.c: No such file or directory.

connectionClose() is called by AbstractConnection's close()method. I tried adding some more sanity checks, such as changing

if (!$this->protocolWriter || !$this->isConnected()) {

to

if (!$this->protocolWriter || !$this->isConnected() || !is_object($this->protocolWriter) || !method_exists($this->protocolWriter, 'connectionClose')) {

to no avail. I'm not really sure what GDB is telling me the problem is, so I'm not really sure of the right way to address it. Immediately returning null from the close method has solved our problem in the short-term, but I fear this will end up causing more problems than it solves.

[michaelklishin]

This library has no native code. The root cause of your segmentation faults is thus somewhere else, perhaps in the runtime.

[frankmayer]

@fixedd the path in your report suggests that you are using a pretty outdated php build (php5-5.3.10). Have you tried this with something newer?

[fixedd]

@frankmayer Sorry, I meant to mention... I tried it on a bunch of versions, the most recent being 5.5.9.

[frankmayer]

@fixedd maybe you're dealing with some kind of obscure zend bug. Unfortunately, even, for example, with PHP 5.5.9 you're using an outdated version of the 5.5 version, which could still have some bug that may or may not already be fixed.

One other thing that comes to mind, since you're mentioning a very high number of messages, is, that you may be reaching the limit of file descriptors / open files in your system, which may cause php to fail.

[fixedd]

@frankmayer The limit thing had occurred to me too, but does that make sense since it's only on the closing call that it dies?

[matteosister]

it happend also to us....we are trying to upgrade a symfony2 project to latest version of RabbitMQBundle. The problems comes from the version of this library...could you please try with the version v2.2.6 and see if works?

[frankmayer]

It could be the limit thing. connectionClose() seems to create a new AMQPWriter and writes to the existing socket, before closing. This should theoretically not be an issue. I 'm just saying that it could, and may be worth a try (along with using the latest php builds, maybe even 5.6.x), in order to narrow down the source of the problem.
Has this been tested with both streamIO and socketIO?

[matteosister]

For us the php version is irrelevant. I tried with the latest minor of 5.5 and 5.6...we are using docker so it's easy...

[Metabor]

We have the same problem, when using this library (with PHP 5.5.9 on Ubuntu and also on windows with PHP 5.5.21).
I think that there somewhere is a recursive loop that got infinite:
http://stackoverflow.com/questions/7327393/why-does-an-infinitely-recursive-function-in-php-cause-a-segfault

[Metabor]

"could you please try with the version v2.2.6 and see if works?"
I was trying it with this version and it worked.
So I checked version 2.4.0, but this version has also this issue for me.
Will now check 2.3.0 to see if the issue is there, too.

[Metabor]

Version 2.3.0 did also not have this issue.
It seems that the issue is there since version 2.4.0.
Maybe I can help with this information.

[Metabor]

We updated the server to PHP 5.6.7 and had to remove XHProf extension (because it was no available for that version).
Now the issue is gone also in the actual version 2.5.0.
Not sure if updating to PHP 5.6.7 helped or if XHProf was the root for that problem.

[frankmayer]

@Metabor
Any chance to test this against the prior PHP version you were running, but with XHProf removed?

[matteosister]

@frankmayer FYI I don't have xhprof and I got the problem anyway....

[fixedd]

Same here, we don't use xhprof.