tor-browser

commit bf9cf5a1b0bc95e4a7521c1935a1038ba305ef69
parent 47eb3572473dfdb826a1b32dc1913b5e37fdf188
Author: Alexandre Poirot <poirot.alex@gmail.com>
Date:   Tue,  6 Jan 2026 15:39:47 +0000

Bug 1990493 - Expose last out of memory stack trace to privileged JavaScript. r=bthrall

Differential Revision: https://phabricator.services.mozilla.com/D265977

Diffstat:
M
dom/base/ChromeUtils.cpp
 | 
6
++++++
M
dom/base/ChromeUtils.h
 | 
1
+
M
dom/chrome-webidl/ChromeUtils.webidl
 | 
5
+++++
M
js/public/Debug.h
 | 
2
++
M
js/src/debugger/Debugger.cpp
 | 
4
++++

5 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/dom/base/ChromeUtils.cpp b/dom/base/ChromeUtils.cpp
@@ -2807,4 +2807,10 @@ void ChromeUtils::EncodeURIForSrcset(GlobalObject&, const nsACString& aIn,
   }
 }
 
+void ChromeUtils::GetLastOOMStackTrace(GlobalObject& aGlobal,
+                                       nsAString& aRetval) {
+  JSContext* cx = aGlobal.Context();
+  aRetval = NS_ConvertUTF8toUTF16(JS_GetLastOOMStackTrace(cx));
+}
+
 }  // namespace mozilla::dom
diff --git a/dom/base/ChromeUtils.h b/dom/base/ChromeUtils.h
@@ -347,6 +347,7 @@ class ChromeUtils {
 
   static Nullable<bool> GetGlobalWindowCommandEnabled(GlobalObject&,
                                                       const nsACString& aName);
+  static void GetLastOOMStackTrace(GlobalObject& aGlobal, nsAString& aRetval);
 
   static void EncodeURIForSrcset(GlobalObject&, const nsACString& aIn,
                                  nsACString& aOut);
diff --git a/dom/chrome-webidl/ChromeUtils.webidl b/dom/chrome-webidl/ChromeUtils.webidl
@@ -864,6 +864,11 @@ partial namespace ChromeUtils {
 
   [Throws]
   Promise<imgIContainer> fetchDecodedImage(URI uri, MozChannel channel);
+
+  // Returns the stack trace captured from the most recent out-of-memory exception,
+  // or null if no OOM stack trace is available. The stack trace shows the JavaScript
+  // call stack at the time the out-of-memory condition occurred
+  DOMString getLastOOMStackTrace();
 };
 
 /*
diff --git a/js/public/Debug.h b/js/public/Debug.h
@@ -29,6 +29,8 @@ class Debugger;
 extern JS_PUBLIC_API bool JS_DefineDebuggerObject(JSContext* cx,
                                                   JS::HandleObject obj);
 
+extern JS_PUBLIC_API const char* JS_GetLastOOMStackTrace(JSContext* cx);
+
 // If the JS execution tracer is running, this will generate a
 // ENTRY_KIND_LABEL_ENTER entry with the specified label.
 // The consumer of the trace can then, for instance, correlate all code running
diff --git a/js/src/debugger/Debugger.cpp b/js/src/debugger/Debugger.cpp
@@ -7411,6 +7411,10 @@ extern JS_PUBLIC_API bool JS_DefineDebuggerObject(JSContext* cx,
   return true;
 }
 
+extern JS_PUBLIC_API const char* JS_GetLastOOMStackTrace(JSContext* cx) {
+  return cx->getOOMStackTrace();
+}
+
 JS_PUBLIC_API bool JS::dbg::IsDebugger(JSObject& obj) {
   /* We only care about debugger objects, so CheckedUnwrapStatic is OK. */
   JSObject* unwrapped = CheckedUnwrapStatic(&obj);