Imagick segfault on Alpine Linux (--without-threads)

[csandanov]

Hi guys,

I'm getting a segfault error while using php extension imagick on Alpine Linux 3.4. The maintainer of imagick (@Danack) extension referred it as a bug in ImageMagick library on Alpine and recommended to compile it with --without-threads flag. The similar issue was posted before in alpine's bug tracker.

After a look up in alpine repository turned out it's already compiled without threads support but as was noted by @Danack:

Apparently CreateMagickThreadKey still does stuff when threads aren't compiled in.

ImageMagick/magick/thread.c

Lines 145 to 166 in ac23b02

	#else
	{
	MagickThreadValue
	**keys;
	keys=(MagickThreadValue **) key;
	*keys=(MagickThreadValue *) AcquireQuantumMemory(1,sizeof(*keys));
	if (*keys != (MagickThreadValue *) NULL)
	{
	(*keys)->number_threads=GetOpenMPMaximumThreads();
	(*keys)->values=AcquireQuantumMemory((*keys)->number_threads,
	sizeof(void *));
	if ((*keys)->values == (void *) NULL)
	*keys=RelinquishMagickMemory(*keys);
	else
	(void) memset((*keys)->values,0,(*keys)->number_threads*
	sizeof(void *));
	(*keys)->destructor=destructor;
	}
	return((*keys != (MagickThreadValue *) NULL) ? MagickTrue : MagickFalse);
	}
	#endif

.

[mikayla-grace]

Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ http://www.imagemagick.org/download/beta/ by sometime tomorrow.

In the mean-time, you should be able to avoid the fault by enabling threads.