Double free when running appstream-generator

[antonio-rojas]

With both AS 0.12.8 + asgen 0.7.7 and AS 0.12.9 + asgen 0.8.0

#0  0x00007f08599da755 in raise () at /usr/lib/libc.so.6
#1  0x00007f08599c5851 in abort () at /usr/lib/libc.so.6
#2  0x00007f0859a1ca38 in __libc_message () at /usr/lib/libc.so.6
#3  0x00007f0859a2325a in  () at /usr/lib/libc.so.6
#4  0x00007f0859a24c1d in _int_free () at /usr/lib/libc.so.6
#5  0x00007f085b177d88 in g_autoptr_cleanup_generic_gfree (p=0x7ee85492b108) at /usr/include/glib-2.0/glib/glib-autocleanups.h:28
#6  0x00007f085b177d88 in as_xml_dump_node_content (node=node@entry=0x7ee82c0df220) at ../AppStream-0.12.9/src/as-xml.c:120
#7  0x00007f085b178249 in as_xml_parse_metainfo_description_node
    (ctx=ctx@entry=0x5646c4e332e0, node=node@entry=0x7ee82c0ded40, func=func@entry=0x7f085b1863a0 <as_xml_metainfo_description_to_cpt>, entity=entity@entry=0x5646c4da2880) at ../AppStream-0.12.9/src/as-xml.c:374
#8  0x00007f085b188f9c in as_component_load_from_xml
    (cpt=cpt@entry=0x5646c4da2880, ctx=ctx@entry=0x5646c4e332e0, node=node@entry=0x7ee82c033e00, error=error@entry=0x7ee85492b2e8)
    at ../AppStream-0.12.9/src/as-component.c:3651
#9  0x00007f085b183b05 in as_metadata_parse (metad=<optimized out>, data=<optimized out>, format=<optimized out>, error=0x7ee85492b2e8)
    at ../AppStream-0.12.9/src/as-metadata.c:531
#10 0x00005646c3103b1e in _D9appstream8MetadataQj5parseMFAyaEQBh1c5types12AsFormatKindZv ()
#11 0x00005646c307ce23 in _D5asgen8handlers14metainfoparser17parseMetaInfoDataFC9appstream8MetadataQjCQCw6result15GeneratorResultxAyaxQeZCQCg9ComponentQk
    ()
#12 0x00005646c2ff77d9 in _D5asgen9extractor13DataExtractor14processPackageMFCQBy8backends10interfaces7PackageZCQDg6result15GeneratorResult ()
#13 0x00005646c2fc7e3d in _D5asgen6engine6Engine15processPackagesMFKACQBq8backends10interfaces7PackageCQCx8handlers11iconhandler11IconHandlerZ14__foreachbody3MFKQDoZi ()
#14 0x00005646c2fd3316 in _D3std11parallelism__T15ParallelForeachTAC5asgen8backends10interfaces7PackageZQCe7opApplyMFMDFKQCcZiZ4doItMFZv ()
#15 0x00007f085ae497c1 in _D3std11parallelism8TaskPool5doJobMFPSQBkQBj12AbstractTaskZv () at /home/arojas/appstream/libphobos2-ldc-shared.so.2.0.87
#16 0x00007f085ae4995b in std.parallelism.TaskPool.startWorkLoop() () at /home/arojas/appstream/libphobos2-ldc-shared.so.2.0.87
#17 0x00007f085b0da03c in thread_entryPoint () at /home/arojas/appstream/libdruntime-ldc-shared.so.2.0.87
#18 0x00007f0859b8857f in start_thread () at /usr/lib/libpthread.so.0
#19 0x00007f0859a9c0e3 in clone () at /usr/lib/libc.so.6

[ximion]

This should be fixed now, thanks for the very useful backtrace!
I do wonder how the faultry code was reached in the first place... Can you by any chance figure out which component/XML/package has produced this particular crash? (maybe by the package name printed to stdout?)

[antonio-rojas]

Thank you for the quick fix. The bogus package is pluma
https://www.archlinux.org/packages/community/x86_64/pluma/download/

[ximion]

Nice, thank you very much!
This confirms that the culprit was indeed an empty <p/> tag.
Also, that metainfo file is so bad, it has never seen a validator. Throws 51 validation errors and 5 warnings here. I also wonder why the description tag itself is translated, that shouldn't happen.
I can use this to maybe improve the validator a bit :-)