Bug 1016629 - g. Avoid ASan flag when copying stack; r=snorp
authorJim Chen <nchen@mozilla.com>
Mon, 28 Jul 2014 13:30:22 -0400
changeset 196370 60a248ab5036b1988ffc2a49ba4da1e25f3a05ab
parent 196369 4592de6b1b145fb6c548f509f0ee28cf565879a1
child 196371 fa87806142d488701617e7d50758be0dbbd8cc0a
push id46863
push usernchen@mozilla.com
push dateMon, 28 Jul 2014 17:30:47 +0000
treeherdermozilla-inbound@fa87806142d4 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewerssnorp
bugs1016629
milestone34.0a1
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Bug 1016629 - g. Avoid ASan flag when copying stack; r=snorp
xpcom/threads/ThreadStackHelper.cpp
--- a/xpcom/threads/ThreadStackHelper.cpp
+++ b/xpcom/threads/ThreadStackHelper.cpp
@@ -607,17 +607,17 @@ ThreadStackHelper::FillStackBuffer()
   // availableBufferSize < 0 if we needed a larger buffer than we reserved.
   // Calculate a new reserve size for next time.
   if (availableBufferSize < 0) {
     mMaxBufferSize = reservedBufferSize - availableBufferSize;
   }
 #endif
 }
 
-void
+MOZ_ASAN_BLACKLIST void
 ThreadStackHelper::FillThreadContext(void* aContext)
 {
 #ifdef MOZ_THREADSTACKHELPER_NATIVE
   if (!mContextToFill) {
     return;
   }
 
 #if defined(XP_LINUX)
@@ -752,16 +752,27 @@ ThreadStackHelper::FillThreadContext(voi
 
 #ifndef MOZ_THREADSTACKHELPER_STACK_GROWS_DOWN
   // If if the stack grows upwards, and we need to recalculate our
   // stack copy's base address. Subtract sizeof(void*) so that the
   // location pointed to by sp is included.
   sp -= stackSize - sizeof(void*);
 #endif
 
+#ifndef MOZ_ASAN
   memcpy(mContextToFill->mStack, reinterpret_cast<void*>(sp), stackSize);
+#else
+  // ASan will flag memcpy for access outside of stack frames,
+  // so roll our own memcpy here.
+  intptr_t* dst = reinterpret_cast<intptr_t*>(&mContextToFill->mStack[0]);
+  const intptr_t* src = reinterpret_cast<intptr_t*>(sp);
+  for (intptr_t len = stackSize; len > 0; len -= sizeof(*src)) {
+    *(dst++) = *(src++);
+  }
+#endif
+
   mContextToFill->mStackBase = uintptr_t(sp);
   mContextToFill->mStackSize = stackSize;
   mContextToFill->mValid = true;
 #endif // MOZ_THREADSTACKHELPER_NATIVE
 }
 
 } // namespace mozilla