Bug 221143 – REGRESSION (r272039): [Big Sur release WK2] imported/w3c/web-platform-tests/media-source/mediasource-changetype-play-implicit.html is a flaky crash

• Status: NEW
• Component: Media

[Robert Jenner]

imported/w3c/web-platform-tests/media-source/mediasource-changetype-play-implicit.html

Test is crashing in Big Sur release WK2.

HISTORY:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fmedia-source%2Fmediasource-changetype-play-implicit.html

CRASH LOG URL:
https://build.webkit.org/results/Apple-BigSur-Release-WK2-Tests/r272060%20(1267)/imported/w3c/web-platform-tests/media-source/mediasource-changetype-play-implicit-crash-log.txt

[Radar WebKit Bug Importer]

<rdar://problem/73762731>

[Robert Jenner]

Bug/Crash reproducible in r272602

Produced bug using test:

run-webkit-test imported/w3c/web-platform-tests/media-source/mediasource-changetype-play-implicit.html --iterations 1000 -f

Regress found crash not occurring in r272035, and started occurring in r272039 

It appears the crashing was introduced in r272039 .

[Radar WebKit Bug Importer]

<rdar://problem/73763073>

[Ryan Haddad]

Created attachment 418782 [details]
crash log

Thread 34 Crashed:: Dispatch queue: SourceBufferPrivateAVFObjC data parser queue
0   libwebrtc.dylib               	0x000000077d5e14a1 webm::WebmParser::DocumentParser::Feed(webm::Callback*, webm::Reader*) + 625 (webm_parser.cc:166)
1   libwebrtc.dylib               	0x000000077d5e1224 webm::WebmParser::Feed(webm::Callback*, webm::Reader*) + 36 (webm_parser.cc:271)
2   com.apple.WebCore             	0x00000007798013b9 WebCore::SourceBufferParserWebM::appendData(WebCore::SourceBufferParser::Segment&&, WTF::CompletionHandler<void ()>&&, WebCore::SourceBufferParser::AppendFlags) + 537 (SourceBufferParserWebM.cpp:627)
3   com.apple.WebCore             	0x000000077817c94a operator() + 72 (SourceBufferPrivateAVFObjC.mm:600) [inlined]
4   com.apple.WebCore             	0x000000077817c94a invocation function for block in WebCore::SourceBufferPrivateAVFObjC::append(WTF::Vector<unsigned char, 0ul, WTF::CrashOnOverflow, 16ul, WTF::FastMalloc>&&) + 106 (SourceBufferPrivateAVFObjC.mm:599)
5   libdispatch.dylib             	0x00007fff201ac5dd _dispatch_call_block_and_release + 12
6   libdispatch.dylib             	0x00007fff201ad7c7 _dispatch_client_callout + 8
7   libdispatch.dylib             	0x00007fff201b0195 _dispatch_continuation_pop + 423
8   libdispatch.dylib             	0x00007fff201af868 _dispatch_async_redirect_invoke + 713
9   libdispatch.dylib             	0x00007fff201bc857 _dispatch_root_queue_drain + 326
10  libdispatch.dylib             	0x00007fff201bcfb8 _dispatch_worker_thread2 + 92
11  libsystem_pthread.dylib       	0x00007fff20355453 _pthread_wqthread + 244
12  libsystem_pthread.dylib       	0x00007fff20354467 start_wqthread + 15