memory leak and errors

[gabrieleolmi]

I have a server running Ubuntu 22.04 where I have apache and php installed. I have recently started using libvips for php, and I have noticed that every time a php script is run, the amount of ram used increases more and more, without being freed. I am forced to use Vips\Config::shutDown() at the end of the script otherwise the server ram gets saturated. I tried to use Vips\Config::cacheSetMax(5) but nothing changes (memory grows more and more).

php file example:

<?php
require __DIR__ . '/vendor/autoload.php';
use Jcupitt\Vips;

$image = Vips\Image::newFromFile($inputImagePath);
//some operations on the width and height of the image
//.....
$image = Vips\Image::thumbnail($inputImagePath, $width, ['height' => $height, 'crop' => 'centre']);
$image->writeToFile($outputImagePath, ['Q' => $quality]);

Also sometimes libvips returns an error:

(process:211949): GLib-GObject-WARNING **: 16:54:47.542: cannot register existing type 'VipsObject'
(process:211949): GLib-CRITICAL **: 16:54:47.542: g_once_init_leave: assertion 'result != 0' failed
(process:211949): GLib-GObject-CRITICAL **: 16:54:47.542: g_type_register_static: assertion 'parent_
type > 0' failed
(process:211949): GLib-CRITICAL **: 16:54:47.542: g_once_init_leave: assertion 'result != 0' failed

libvips42 version: 8.12.1
php-vips version: 2.0.3

[jcupitt]

Hi @gabrieleolmi,

How is apache set up? I suppose you have fastcgi and a persistent process for requests, is that right?

[gabrieleolmi]

FPM/FastCGI

[kleisauke]

Perhaps this is a symptom of https://www.php.net/manual/en/language.oop5.decon.php#105368? I tried to debug that using commit kleisauke@d20ec0d and see about 45 references still alive after the OK print on the test suite.

[jcupitt]

Huh that's a bit surprising, there shouldn't be any circular references.

Does adding gc_collect_cycles() to your php fix this?

[kleisauke]

Ah, my bad. You're right, there shouldn't be any circular references. Commit kleisauke@73d05c0 fixes that, it seems we need to explicitly unset the images in tearDown() (just like teardown_class in libvips' test suite).

[kleisauke]

The cannot register existing type error can probably be fixed if libvips is linked with -Wl,-z,nodelete, see: #142 (comment)

Hopefully that would also fix the memory leak you were seeing.

[jcupitt]

@gabrieleolmi libvips 8.13 is out now with Kleis's linking improvement (setting nodelete).

https://github.com/libvips/libvips/releases

Any testing would be great.

[gabrieleolmi]

The cannot register existing type error can probably be fixed if libvips is linked with -Wl,-z,nodelete, see: #142 (comment)

Hopefully that would also fix the memory leak you were seeing.

I built libvips 8.13 from source and i did some quick tests. Vips\Config::cacheSetMax() seems to work and no more GLib errors appear 😀.

[jcupitt]

Woo! Great, thank you for doing the testing.

[gabrieleolmi]

Errors when calling Vips\Config::shutDown();

[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.461: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.461: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.462: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.462: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.462: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.462: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.462: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.463: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.463: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.463: g_hash_table_insert_internal: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 said into stderr: "(process:89482): GLib-CRITICAL **: 23:02:06.463: g_hash_table_lookup: assertion 'hash_table != NULL' failed"
[23-Jul-2022 23:02:06] WARNING: [pool www] child 89482 exited on signal 11 (SIGSEGV - core dumped) after 166.434485 seconds from start
[23-Jul-2022 23:02:06] NOTICE: [pool www] child 90288 started

[jcupitt]

You can't use libvips again after shutdown, and you can't init again. Only call it just before process exit.

[gabrieleolmi]

I called Vips\Config::shutDown(); at the end of the script. So i think it's the fastcgi process that keeps running.

[jcupitt]

Yes, fastcgi is a persistent process, Don't call shutdown if you use it.