Changeset 292075 in webkit

Timestamp:

Mar 29, 2022, 3:10:45 PM (5 years ago)

Author:

Patrick Angle

Message:

Web Inspector: Add check for null entryScope in JSC::Debugger::detach
​https://bugs.webkit.org/show_bug.cgi?id=238518

Reviewed by Devin Rousso.

A virtual machine may not always have an entryScope, which can occur if a JSGlobalObject is being destructed
(which will call into JSC::Debugger::Detach) before a VMEntryScope is created or after a VMEntryScope has
fallen out of scope, causing the VM's entryScope to be null again. In the original internal issue that led to
finding this, this most commonly occurred in conjunction with page refresh while the debugger was paused.

Because it is possible that we were previously paused in the VM that now has no entryScope, we should go ahead
and unpause.

• debugger/Debugger.cpp:

(JSC::Debugger::detach):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• debugger/Debugger.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2022-03-29  Patrick Angle  <pangle@apple.com>
+
+        Web Inspector: Add check for null `entryScope` in JSC::Debugger::detach
+        https://bugs.webkit.org/show_bug.cgi?id=238518
+
+        Reviewed by Devin Rousso.
+
+        A virtual machine may not always have an `entryScope`, which can occur if a `JSGlobalObject` is being destructed
+        (which will call into `JSC::Debugger::Detach`) before a `VMEntryScope` is created or after a `VMEntryScope` has
+        fallen out of scope, causing the VM's `entryScope` to be null again. In the original internal issue that led to
+        finding this, this most commonly occurred in conjunction with page refresh while the debugger was paused.
+
+        Because it is possible that we were previously paused in the VM that now has no `entryScope`, we should go ahead
+        and unpause.
+
+        * debugger/Debugger.cpp:
+        (JSC::Debugger::detach):
+
 2022-03-29  Patrick Angle  <pangle@apple.com>
 

trunk/Source/JavaScriptCore/debugger/Debugger.cpp

@@ -172 +172 @@
     JSLockHolder locker(vm);
 
-    if (m_isPaused && m_currentCallFrame && vm.entryScope->globalObject() == globalObject) {
+    if (m_isPaused && m_currentCallFrame && (!vm.isEntered() || vm.entryScope->globalObject() == globalObject)) {
         m_currentCallFrame = nullptr;
         m_pauseOnCallFrame = nullptr;