Bug 287479 – [GStreamer] Crash in gst_gl_upload_transform_caps

• Component: Media
• Status: RESOLVED INVALID

[Michael Catanzaro]

Today when using Newsflash I hit a web process crash deep in GStreamer. Not sure whether it's a GStreamer bug or a WebKit bug, so starting here.

Thread 1 (Thread 0x7fa0dc9fb6c0 (LWP 105)):
#0  0x00007fa2e472c3eb in gst_gl_upload_transform_caps (upload=upload@entry=0x55e9f0ba8c90 [GstGLUpload|glupload0], context=context@entry=0x7fa0e4008b80 [GstGLContextEGL|glcontextegl0], direction=direction@entry=GST_PAD_SRC, caps=caps@entry=0x7fa0c0101460 [GstCaps], filter=filter@entry=0x0) at ../gst-libs/gst/gl/gstglupload.c:3350
#1  0x00007fa224458f11 in _gst_gl_upload_element_transform_caps (bt=0x55e9f0ba0e00 [GstGLUploadElement|gluploadelement0], direction=GST_PAD_SRC, caps=0x7fa0c0101460 [GstCaps], filter=0x0) at ../ext/gl/gstgluploadelement.c:198
#2  0x00007fa2e4af75e8 in gst_base_transform_transform_caps (trans=trans@entry=0x55e9f0ba0e00 [GstGLUploadElement|gluploadelement0], direction=GST_PAD_SRC, caps=caps@entry=0x7fa0c0101460 [GstCaps], filter=filter@entry=0x0) at ../libs/gst/base/gstbasetransform.c:474
#3  0x00007fa2e4afad64 in gst_base_transform_query_caps (trans=0x55e9f0ba0e00 [GstGLUploadElement|gluploadelement0], pad=0x55e9f0ba1130 [GstPad|sink], filter=0x0) at ../libs/gst/base/gstbasetransform.c:698
#4  gst_base_transform_default_query (trans=0x55e9f0ba0e00 [GstGLUploadElement|gluploadelement0], direction=<optimized out>, query=0x7fa0c0289ac0 [GstQuery]) at ../libs/gst/base/gstbasetransform.c:1598
#5  0x00007fa2e49e97d9 in gst_pad_query (pad=pad@entry=0x55e9f0ba1130 [GstPad|sink], query=query@entry=0x7fa0c0289ac0 [GstQuery]) at ../gst/gstpad.c:4228
#6  0x00007fa2e49ea353 in gst_pad_peer_query (pad=0x55e9f0babe00 [GstProxyPad|proxypad4], query=0x7fa0c0289ac0 [GstQuery]) at ../gst/gstpad.c:4365
#7  0x00007fa2e4a3402e in query_caps_func (pad=0x55e9f0babe00 [GstProxyPad|proxypad4], data=0x7fa0dc9f7ac0) at ../gst/gstutils.c:2816
#8  0x00007fa2e49f0141 in gst_pad_forward (pad=0x55e9f0bb0ba0 [GstGhostPad|sink], forward=0x7fa2e4a34000 <query_caps_func>, user_data=0x7fa0dc9f7ac0) at ../gst/gstpad.c:3110
#9  0x00007fa2e4a3427f in gst_pad_proxy_query_caps (pad=0x55e9f0bb0ba0 [GstGhostPad|sink], query=0x7fa0c0289ac0 [GstQuery]) at ../gst/gstutils.c:2868
#10 0x00007fa2e49f09ea in gst_pad_query_caps_default (pad=0x55e9f0bb0ba0 [GstGhostPad|sink], query=0x7fa0c0289ac0 [GstQuery]) at ../gst/gstpad.c:3295

I think I might have seen this crash before, but if so it's pretty rare.

[Michael Catanzaro]

Created attachment 474199 [details]
All-threads backtrace

[Michael Catanzaro]

Created attachment 474200 [details]
Full backtrace of crash thread

[Philippe Normand]

With main?

How to reproduce this?

Is it a flaky crash or consistently crashing?

[Philippe Normand]

I use newsflash (flatpak) as well, just tell me which feed to load :)

[Philippe Normand]

A GST_DEBUG="gl*:6" log might be useful as well.

[Michael Catanzaro]

I've actually now hit this twice today, but it doesn't seem to be reliably caused by any particular feed. I'll keep an eye out.

I had been thinking this was a rare crash, but since it's happened twice, that must not be true.

[Philippe Normand]

That should be reported to GStreamer gitlab if it ever happens again.