fast/files/workers/worker-read-blob-sync.html sometimes (rarely) crashes like this. First crash still remembered by flakiness dashboard on April 8, latest one yesterday night (after the fix in <https://webkit.org/b/132032>). http://build.webkit.org/results/Apple%20Mavericks%20Debug%20WK1%20(Tests)/r167699%20(4861)/fast/files/workers/worker-read-blob-sync-crash-log.txt Thread 15 Crashed:: JSC Compilation Thread 0 com.apple.JavaScriptCore 0x000000010a3f60aa WTFCrash + 42 (Assertions.cpp:333) 1 com.apple.JavaScriptCore 0x0000000109de8dc2 JSC::DFG::AbstractValue::checkConsistency() const + 482 (DFGAbstractValue.cpp:284) 2 com.apple.JavaScriptCore 0x0000000109de8b0d JSC::DFG::AbstractValue::setMostSpecific(JSC::DFG::Graph&, JSC::JSValue) + 253 (DFGAbstractValue.cpp:53) 3 com.apple.JavaScriptCore 0x0000000109eb2e76 JSC::DFG::Graph::Graph(JSC::VM&, JSC::DFG::Plan&, JSC::DFG::LongLivedState&) + 966 (DFGGraph.cpp:75) 4 com.apple.JavaScriptCore 0x0000000109f3dc65 JSC::DFG::Plan::compileInThreadImpl(JSC::DFG::LongLivedState&) + 181 (DFGPlan.cpp:192) 5 com.apple.JavaScriptCore 0x0000000109f3d8e4 JSC::DFG::Plan::compileInThread(JSC::DFG::LongLivedState&, JSC::DFG::ThreadData*) + 292 (DFGPlan.cpp:155) 6 com.apple.JavaScriptCore 0x0000000109fe0760 JSC::DFG::Worklist::runThread(JSC::DFG::ThreadData*) + 528 (DFGWorklist.cpp:302) 7 com.apple.JavaScriptCore 0x0000000109fdf374 JSC::DFG::Worklist::threadFunction(void*) + 36 (DFGWorklist.cpp:326) 8 com.apple.JavaScriptCore 0x000000010a4482a0 WTF::threadEntryPoint(void*) + 144 (Threading.cpp:68) 9 com.apple.JavaScriptCore 0x000000010a448f88 WTF::wtfThreadEntryPoint(void*) + 296 (ThreadingPthreads.cpp:168) 10 libsystem_pthread.dylib 0x00007fff959f1899 _pthread_body + 138 11 libsystem_pthread.dylib 0x00007fff959f172a _pthread_start + 137 12 libsystem_pthread.dylib 0x00007fff959f5fc9 thread_start + 13
<rdar://problem/16700180>
I don't see any recent assertions on this test.