Changeset 234528 in webkit for trunk/Source/JavaScriptCore/tools/CodeProfiling.cpp

Timestamp:

Aug 2, 2018, 5:14:11 PM (7 years ago)

Author:

[email protected]

Message:

Source/JavaScriptCore:
Reading instructionPointer from PlatformRegisters may fail when using pointer profiling
​https://bugs.webkit.org/show_bug.cgi?id=188271
<rdar://problem/42850884>

Reviewed by Michael Saboff.

This patch defends against the instructionPointer containing garbage bits.
See radar for details.

• runtime/MachineContext.h:

(JSC::MachineContext::instructionPointer):

• runtime/SamplingProfiler.cpp:

(JSC::SamplingProfiler::takeSample):

• runtime/VMTraps.cpp:

(JSC::SignalContext::SignalContext):
(JSC::SignalContext::tryCreate):

• tools/CodeProfiling.cpp:

(JSC::profilingTimer):

• tools/SigillCrashAnalyzer.cpp:

(JSC::SignalContext::SignalContext):
(JSC::SignalContext::tryCreate):
(JSC::SignalContext::dump):
(JSC::installCrashHandler):

• wasm/WasmFaultSignalHandler.cpp:

(JSC::Wasm::trapHandler):

Source/WTF:
Reading instructionPointer from PlatformRegisters may fail when using pointer tagging
​https://bugs.webkit.org/show_bug.cgi?id=188271
<rdar://problem/42850884>

Reviewed by Michael Saboff.

• wtf/PtrTag.h:

(WTF::isTaggedWith):
(WTF::usesPointerTagging):

File:

• trunk/Source/JavaScriptCore/tools/CodeProfiling.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/tools/CodeProfiling.cpp

@@ -72 +72 @@
 {
     PlatformRegisters& platformRegisters = WTF::registersFromUContext(static_cast<ucontext_t*>(uap));
-    CodeProfiling::sample(
-        MachineContext::instructionPointer(platformRegisters).untaggedExecutableAddress(),
-        reinterpret_cast<void**>(MachineContext::framePointer(platformRegisters)));
+    if (auto instructionPointer = MachineContext::instructionPointer(platformRegisters)) {
+        CodeProfiling::sample(
+            instructionPointer->untaggedExecutableAddress(),
+            reinterpret_cast<void**>(MachineContext::framePointer(platformRegisters)));
+    }
 }
 #endif