Bug 149973 – Crash when dumping bytecode while profiling

• Status: NEW
• Component: JavaScriptCore

[Mark Hahnenberg]

Backtrace:

Thread 21 Crashed:: DFG Worklist Worker Thread
0   com.apple.JavaScriptCore      	0x0000000114f7cc01 JSC::AccessCase::dump(WTF::PrintStream&) const + 17
1   com.apple.JavaScriptCore      	0x0000000114f82e3d JSC::PolymorphicAccess::dump(WTF::PrintStream&) const + 109
2   com.apple.JavaScriptCore      	0x0000000114a0e5b9 JSC::CodeBlock::printGetByIdCacheStatus(WTF::PrintStream&, JSC::ExecState*, int, WTF::HashMap<JSC::CodeOrigin, JSC::StructureStubInfo*, JSC::CodeOriginApproximateHash, WTF::HashTraits<JSC::CodeOrigin>, WTF::HashTraits<JSC::StructureStubInfo*> > const&) + 809
3   com.apple.JavaScriptCore      	0x0000000114a106a2 JSC::CodeBlock::dumpBytecode(WTF::PrintStream&, JSC::ExecState*, JSC::Instruction const*, JSC::Instruction const*&, WTF::HashMap<JSC::CodeOrigin, JSC::StructureStubInfo*, JSC::CodeOriginApproximateHash, WTF::HashTraits<JSC::CodeOrigin>, WTF::HashTraits<JSC::StructureStubInfo*> > const&, WTF::HashMap<JSC::CodeOrigin, JSC::CallLinkInfo*, JSC::CodeOriginApproximateHash, WTF::HashTraits<JSC::CodeOrigin>, WTF::HashTraits<JSC::CallLinkInfo*> > const&) + 1362
4   com.apple.JavaScriptCore      	0x0000000114a18eb1 JSC::CodeBlock::dumpBytecode(WTF::PrintStream&, unsigned int, WTF::HashMap<JSC::CodeOrigin, JSC::StructureStubInfo*, JSC::CodeOriginApproximateHash, WTF::HashTraits<JSC::CodeOrigin>, WTF::HashTraits<JSC::StructureStubInfo*> > const&, WTF::HashMap<JSC::CodeOrigin, JSC::CallLinkInfo*, JSC::CodeOriginApproximateHash, WTF::HashTraits<JSC::CodeOrigin>, WTF::HashTraits<JSC::CallLinkInfo*> > const&) + 81
5   com.apple.JavaScriptCore      	0x0000000114f9cd5c JSC::Profiler::BytecodeSequence::BytecodeSequence(JSC::CodeBlock*) + 700
6   com.apple.JavaScriptCore      	0x0000000114fa31d5 JSC::Profiler::ProfiledBytecodes::ProfiledBytecodes(JSC::Profiler::Bytecodes*, JSC::CodeBlock*) + 21
7   com.apple.JavaScriptCore      	0x0000000114f9da8f JSC::Profiler::Compilation::addProfiledBytecodes(JSC::Profiler::Database&, JSC::CodeBlock*) + 95
8   com.apple.JavaScriptCore      	0x0000000114a95af2 JSC::DFG::ByteCodeParser::parseCodeBlock() + 98
9   com.apple.JavaScriptCore      	0x0000000114a81aad bool JSC::DFG::ByteCodeParser::attemptToInlineCall<JSC::DFG::ByteCodeParser::handleInlining(JSC::DFG::Node*, int, JSC::CallLinkStatus const&, int, JSC::VirtualRegister, JSC::VirtualRegister, unsigned int, int, unsigned int, JSC::DFG::NodeType, JSC::InlineCallFrame::Kind, unsigned int)::$_0>(JSC::DFG::Node*, int, JSC::CallVariant, int, int, unsigned int, JSC::InlineCallFrame::Kind, JSC::DFG::ByteCodeParser::CallerLinkability, unsigned int, unsigned int&, JSC::DFG::ByteCodeParser::handleInlining(JSC::DFG::Node*, int, JSC::CallLinkStatus const&, int, JSC::VirtualRegister, JSC::VirtualRegister, unsigned int, int, unsigned int, JSC::DFG::NodeType, JSC::InlineCallFrame::Kind, unsigned int)::$_0 const&) + 2701
10  com.apple.JavaScriptCore      	0x0000000114a7d0f1 JSC::DFG::ByteCodeParser::handleInlining(JSC::DFG::Node*, int, JSC::CallLinkStatus const&, int, JSC::VirtualRegister, JSC::VirtualRegister, unsigned int, int, unsigned int, JSC::DFG::NodeType, JSC::InlineCallFrame::Kind, unsigned int) + 945
11  com.apple.JavaScriptCore      	0x0000000114a7cbd8 JSC::DFG::ByteCodeParser::handleCall(int, JSC::DFG::NodeType, JSC::InlineCallFrame::Kind, unsigned int, JSC::DFG::Node*, int, int, JSC::CallLinkStatus, unsigned int) + 312
12  com.apple.JavaScriptCore      	0x0000000114a7ca50 JSC::DFG::ByteCodeParser::handleCall(int, JSC::DFG::NodeType, JSC::CallMode, unsigned int, JSC::DFG::Node*, int, int, JSC::CallLinkStatus) + 432
13  com.apple.JavaScriptCore      	0x0000000114a7c825 JSC::DFG::ByteCodeParser::handleCall(int, JSC::DFG::NodeType, JSC::CallMode, unsigned int, int, int, int) + 277
14  com.apple.JavaScriptCore      	0x0000000114a89c62 JSC::DFG::ByteCodeParser::parseBlock(unsigned int) + 8450
15  com.apple.JavaScriptCore      	0x0000000114a95f8b JSC::DFG::ByteCodeParser::parseCodeBlock() + 1275
16  com.apple.JavaScriptCore      	0x0000000114a96306 JSC::DFG::ByteCodeParser::parse() + 262
17  com.apple.JavaScriptCore      	0x0000000114a96589 JSC::DFG::parse(JSC::DFG::Graph&) + 425
18  com.apple.JavaScriptCore      	0x0000000114b912d0 JSC::DFG::Plan::compileInThreadImpl(JSC::DFG::LongLivedState&) + 256
19  com.apple.JavaScriptCore      	0x0000000114b90e91 JSC::DFG::Plan::compileInThread(JSC::DFG::LongLivedState&, JSC::DFG::ThreadData*) + 577
20  com.apple.JavaScriptCore      	0x0000000114c3e876 JSC::DFG::Worklist::runThread(JSC::DFG::ThreadData*) + 758
21  com.apple.JavaScriptCore      	0x000000011507d8d2 WTF::threadEntryPoint(void*) + 178
22  com.apple.JavaScriptCore      	0x000000011507dcff WTF::wtfThreadEntryPoint(void*) + 15
23  libsystem_pthread.dylib       	0x00007fff9780905a _pthread_body + 131
24  libsystem_pthread.dylib       	0x00007fff97808fd7 _pthread_start + 176
25  libsystem_pthread.dylib       	0x00007fff978063ed thread_start + 13

My guess is that the dumping code isn't taking the CodeBlock's concurrent JIT lock despite the fact that it's looking at inline-cache related things while dumping. The BytecodeSequence constructor takes the lock in its first loop but fails to do so in the second loop.

[Mark Hahnenberg]

To repro:

Build svn revision 190816

JSC_enableProfiler=true JSC_PROFILER_PATH="/Users/mhahnenberg/Desktop" Tools/Scripts/run-safari --release

Load facebook.com

[Mark Hahnenberg]

Hmm, I tried adding a lock in the place I suggested but it caused a deadlock with another dumping related thing deeper in the stack. So it seems like we need something more fine-grained.