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Fix bad access to detached ArrayBuffer in $growMemory. #24524

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Merged
merged 1 commit into from
Jun 13, 2025
Merged

Fix bad access to detached ArrayBuffer in $growMemory. #24524

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13 changes: 5 additions & 8 deletions src/lib/libcore.js
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Original file line number Diff line number Diff line change
Expand Up @@ -174,27 +174,24 @@ addToLibrary({
// Grows the wasm memory to the given byte size, and updates the JS views to
// it. Returns 1 on success, 0 on error.
$growMemory: (size) => {
var b = wasmMemory.buffer;
var pages = ((size - b.byteLength + {{{ WASM_PAGE_SIZE - 1 }}}) / {{{ WASM_PAGE_SIZE }}}) | 0;
var oldHeapSize = wasmMemory.buffer.byteLength;
var pages = ((size - oldHeapSize + {{{ WASM_PAGE_SIZE - 1 }}}) / {{{ WASM_PAGE_SIZE }}}) | 0;
#if RUNTIME_DEBUG
dbg(`growMemory: ${size} (+${size - b.byteLength} bytes / ${pages} pages)`);
#endif
#if MEMORYPROFILER
var oldHeapSize = b.byteLength;
dbg(`growMemory: ${size} (+${size - oldHeapSize} bytes / ${pages} pages)`);
#endif
try {
// round size grow request up to wasm page size (fixed 64KB per spec)
wasmMemory.grow({{{ toIndexType('pages') }}}); // .grow() takes a delta compared to the previous size
updateMemoryViews();
#if MEMORYPROFILER
if (typeof emscriptenMemoryProfiler != 'undefined') {
emscriptenMemoryProfiler.onMemoryResize(oldHeapSize, b.byteLength);
emscriptenMemoryProfiler.onMemoryResize(oldHeapSize, wasmMemory.buffer.byteLength);
}
#endif
return 1 /*success*/;
} catch(e) {
#if ASSERTIONS
err(`growMemory: Attempted to grow heap from ${b.byteLength} bytes to ${size} bytes, but got error: ${e}`);
err(`growMemory: Attempted to grow heap from ${oldHeapSize} bytes to ${size} bytes, but got error: ${e}`);
#endif
}
// implicit 0 return to save code size (caller will cast "undefined" into 0
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