Bug 257455 – [GStreamer] codecForStreamId() should return empty string when codec is unknown

• Component: Platform
• Status: RESOLVED FIXED

[Philippe Normand]

Prospective fix for racy crashes like this

Thread 1 (Thread 0x7f324d900540 (LWP 778165)):
#0  0x00007f325900bf5e in WTF::String WTF::HashMap<WTF::String, WTF::String, WTF::DefaultHash<WTF::String>, WTF::HashTraits<WTF::String>, WTF::HashTraits<WTF::String>, WTF::HashTableTraits>::get<WTF::IdentityHashTranslator<WTF::HashMap<WTF::String, WTF::String, WTF::DefaultHash<WTF::String>, WTF::HashTraits<WTF::String>, WTF::HashTraits<WTF::String>, WTF::HashTableTraits>::KeyValuePairTraits, WTF::DefaultHash<WTF::String> >, WTF::String>(WTF::String const&) const () at /app/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.1.so.0
#1  0x00007f325942d184 in WebCore::MediaPlayerPrivateGStreamer::codecForStreamId(WTF::String const&) () at /app/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.1.so.0
#2  0x00007f3259453e0c in WebCore::VideoTrackPrivateGStreamer::capsChanged(WTF::String const&, WTF::GRefPtr<_GstCaps> const&) () at /app/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.1.so.0
#3  0x00007f325944486e in WTF::Detail::CallableWrapper<WebCore::TrackPrivateBaseGStreamer::setPad(WTF::GRefPtr<_GstPad>&&)::{lambda(_GstPad*, _GstPadProbeInfo*, WebCore::TrackPrivateBaseGStreamer*)#1}::operator()(_GstPad*, _GstPadProbeInfo*, WebCore::TrackPrivateBaseGStreamer*) const::{lambda()#1}, void>::call() () at /app/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.1.so.0
#4  0x00007f32562cb97a in WTF::RunLoop::performWork() () at /app/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.1.so.0
#5  0x00007f3256344779 in WTF::RunLoop::RunLoop()::{lambda(void*)#1}::_FUN(void*) () at /app/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.1.so.0
#6  0x00007f32563451ef in WTF::RunLoop::{lambda(_GSource*, int (*)(void*), void*)#1}::_FUN(_GSource*, int (*)(void*), void*) () at /app/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.1.so.0
#7  0x00007f32520d1c37 in g_main_dispatch (context=0x55f9018eb130) at ../glib/gmain.c:3419
#8  g_main_context_dispatch (context=0x55f9018eb130) at ../glib/gmain.c:4137
#9  0x00007f3252128028 in g_main_context_iterate.constprop.0 (context=0x55f9018eb130, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4213
#10 0x00007f32520d12af in g_main_loop_run (loop=0x55f901919510) at ../glib/gmain.c:4413
#11 0x00007f3256345320 in WTF::RunLoop::run() () at /app/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.1.so.0
#12 0x00007f325936e05e in int WebKit::AuxiliaryProcessMain<WebKit::WebProcessMainGtk>(int, char**) () at /app/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.1.so.0
#13 0x00007f3251a6c54a in __libc_start_call_main (main=main@entry=0x55f8ff974920 <main>, argc=argc@entry=4, argv=argv@entry=0x7ffca8e44fe8) at ../sysdeps/nptl/libc_start_call_main.h:58
#14 0x00007f3251a6c60b in __libc_start_main_impl (main=0x55f8ff974920 <main>, argc=4, argv=0x7ffca8e44fe8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=<optimized out>) at ../csu/libc-start.c:389
#15 0x000055f8ff974855 in _start () at ../sysdeps/x86_64/start.S:115

[Philippe Normand]

Pull request: https://github.com/WebKit/WebKit/pull/14453

[EWS]

Committed 264664@main (aeffd122d8e7): <https://commits.webkit.org/264664@main>

Reviewed commits have been landed. Closing PR #14453 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/109993002>