From 1a21dce7357cb20f5b79779f6fd3b3e1c6ec234a Mon Sep 17 00:00:00 2001
From: Fredrik Söderquist <fs@opera.com>
Date: Thu, 08 Oct 2026 07:15:33 -0700
Subject: [PATCH] Fix iteration in SVGDocumentResourceTracker::DisposeUnobserved()

The tracked_resources_ set could potentially be mutated by the disposal
of a SVGResourceDocumentContent, so make a copy before iterating.

Since SVGDocumentResourceTracker::Dispose() could potentially suffer
from a similar issue, adjust it too.

Fixed: 570050934
Change-Id: Iec67ad5ced154acad56a7bb30a2c4edb6fbfb507
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8525706
Auto-Submit: Fredrik Söderquist <fs@opera.com>
Commit-Queue: Philip Rogers <pdr@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1714468}
---
diff --git a/third_party/blink/renderer/core/svg/svg_document_resource_tracker.cc b/third_party/blink/renderer/core/svg/svg_document_resource_tracker.cc
index 26eecce..819d97d 100644
--- a/third_party/blink/renderer/core/svg/svg_document_resource_tracker.cc
+++ b/third_party/blink/renderer/core/svg/svg_document_resource_tracker.cc
@@ -36,11 +36,14 @@
       cache_identifier_(cache_identifier) {}
 
 void SVGDocumentResourceTracker::Dispose() {
-  for (const auto& resource : tracked_resources_) {
+  is_disposed_ = true;
+
+  HeapHashSet<Member<SVGDocumentResource>> to_dispose;
+  to_dispose.swap(tracked_resources_);
+  for (const auto& resource : to_dispose) {
     resource->GetContent()->Dispose();
   }
   MemoryCache::Get()->EvictResourcesForCacheIdentifier(cache_identifier_);
-  tracked_resources_.clear();
 }
 
 void SVGDocumentResourceTracker::DisposeUnobserved() {
@@ -49,12 +52,17 @@
   HeapVector<Member<SVGDocumentResource>> to_remove;
   for (const auto& resource : tracked_resources_) {
     if (!resource->GetContent()->HasObservers()) {
-      resource->GetContent()->Dispose();
       to_remove.push_back(resource);
       MemoryCache::Get()->Remove(resource);
     }
   }
   tracked_resources_.RemoveAll(to_remove);
+
+  // Perform disposal from `to_remove` since Dispose() may cause additional
+  // resources to be added (i.e mutate `tracked_resources_`).
+  for (const auto& resource : to_remove) {
+    resource->GetContent()->Dispose();
+  }
 }
 
 void SVGDocumentResourceTracker::ProcessCustomWeakness(
@@ -86,6 +94,7 @@
 }
 
 void SVGDocumentResourceTracker::AddResource(SVGDocumentResource* resource) {
+  CHECK(!is_disposed_);
   tracked_resources_.insert(resource);
 }
 
diff --git a/third_party/blink/renderer/core/svg/svg_document_resource_tracker.h b/third_party/blink/renderer/core/svg/svg_document_resource_tracker.h
index e8d346a..61ccf15 100644
--- a/third_party/blink/renderer/core/svg/svg_document_resource_tracker.h
+++ b/third_party/blink/renderer/core/svg/svg_document_resource_tracker.h
@@ -43,6 +43,7 @@
       const String& cache_identifier);
 
   void Dispose();
+  bool IsDisposed() const { return is_disposed_; }
 
   void Trace(Visitor*) const;
 
@@ -59,6 +60,7 @@
   HeapHashSet<Member<SVGDocumentResource>> tracked_resources_;
   scoped_refptr<base::SingleThreadTaskRunner> dispose_task_runner_;
   bool dispose_task_pending_ = false;
+  bool is_disposed_ = false;
   String cache_identifier_;
 };
 
diff --git a/third_party/blink/renderer/core/svg/svg_resource_document_content.cc b/third_party/blink/renderer/core/svg/svg_resource_document_content.cc
index 8ad1a6a..05662b2 100644
--- a/third_party/blink/renderer/core/svg/svg_resource_document_content.cc
+++ b/third_party/blink/renderer/core/svg/svg_resource_document_content.cc
@@ -290,6 +290,9 @@
 
   Page* page = document.GetPage();
   auto& cache = page->GetSVGDocumentResourceTracker();
+  if (cache.IsDisposed()) {
+    return nullptr;
+  }
 
   SVGDocumentResource* resource = SVGDocumentResource::Fetch(
       params, document.Fetcher(), page->GetAgentGroupScheduler());