[sandbox] Temporarily mark ArrayBufferExtensions as non-managed

Samuel Groß · V8 LUCI CQ · commit e9dbc07e5295 · 2024-04-18T08:19:26.000Z
There is currently an issue where detaching an ArrayBuffer's extension can interfere with table compaction and the zapping mechanism of managed external resources. This CL temporarily disables the managed external resource mechanism for ArrayBufferExtensions until the best approach for fixing the issue has been determined. Bug: chromium:333493383 Change-Id: Ic5b97e4a427032979bfb9d50abd0984172e5f76b Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/5464461 Commit-Queue: Samuel Groß <saelo@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Cr-Commit-Position: refs/heads/main@{#93425}
diff --git a/include/v8-internal.h b/include/v8-internal.h
@@ -518,8 +518,8 @@ constexpr uint64_t kAllExternalPointerTypeTags[] = {
   /* External resources whose lifetime is tied to */     \
   /* their entry in the external pointer table but */    \
   /* which are not referenced via a Managed */           \
-  V(kArrayBufferExtensionTag,                   TAG(57)) \
-  V(kLastManagedResourceTag,                    TAG(57))
+  V(kLastManagedResourceTag,                    TAG(56)) \
+  V(kArrayBufferExtensionTag,                   TAG(57))
 
 // All external pointer tags.
 #define ALL_EXTERNAL_POINTER_TAGS(V) \
diff --git a/src/sandbox/external-pointer-table-inl.h b/src/sandbox/external-pointer-table-inl.h
@@ -302,7 +302,9 @@ void ExternalPointerTable::Space::NotifyExternalPointerFieldInvalidated(
 }
 
 void ExternalPointerTable::ManagedResource::ZapExternalPointerTableEntry() {
-  owning_table_->Zap(ept_entry_);
+  if (owning_table_) {
+    owning_table_->Zap(ept_entry_);
+  }
   ept_entry_ = kNullExternalPointerHandle;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -302,7 +302,9 @@ void ExternalPointerTable::Space::NotifyExternalPointerFieldInvalidated(`
`302`	`302`	`}`
`303`	`303`
`304`	`304`	`void ExternalPointerTable::ManagedResource::ZapExternalPointerTableEntry() {`
`305`		`- owning_table_->Zap(ept_entry_);`
	`305`	`+ if (owning_table_) {`
	`306`	`+ owning_table_->Zap(ept_entry_);`
	`307`	`+ }`
`306`	`308`	`ept_entry_ = kNullExternalPointerHandle;`
`307`	`309`	`}`
`308`	`310`