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Fix edge case in memory reallocation algorithm in wasm-rt.cpp

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刘皓 2025-05-10 11:09:20 -04:00
parent fc744ab6c6
commit 09ed08c087
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GPG key ID: 7901753DB465B711
1 changed files with 9 additions and 5 deletions
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14
binding-sandbox/wasm-rt.cpp
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@ -74,6 +74,7 @@ extern "C" void wasm_rt_allocate_memory(wasm_rt_memory_t *memory, uint32_t initi
throw std::bad_alloc();
}
memory->capacity = (uint64_t)WASM_MIN_PAGES * (uint64_t)WASM_PAGE_SIZE;
mkxp_retro::log_printf(RETRO_LOG_DEBUG, "VM memory initialized with capacity %llu bytes (%u pages)\n", memory->capacity, WASM_MIN_PAGES);
memory->private_data = (uint8_t *)std::malloc(std::max((size_t)memory->size, (size_t)WASM_MIN_PAGES * (size_t)WASM_PAGE_SIZE));
if (memory->private_data == nullptr) {
throw std::bad_alloc();
@ -98,18 +99,21 @@ extern "C" uint32_t wasm_rt_grow_memory(wasm_rt_memory_t *memory, uint32_t pages
return -1;
}
mkxp_retro::log_printf(RETRO_LOG_INFO, "VM memory grown to %u pages\n", new_pages);
mkxp_retro::log_printf(RETRO_LOG_DEBUG, "VM memory grown to %llu bytes (%u pages)\n", new_size, new_pages);
if (new_size > memory->capacity) {
// Increase capacity by 12.5%
size_t new_capacity = memory->capacity;
if (new_capacity < memory->capacity) { // Unsigned integer overflow
return -1;
}
new_capacity += memory->capacity >> 3;
if (new_capacity < memory->capacity) { // Unsigned integer overflow
return -1;
while (new_size > new_capacity) {
// Increase capacity by 12.5%
new_capacity += new_capacity >> 3;
if (new_capacity < memory->capacity) { // Unsigned integer overflow
return -1;
}
}
mkxp_retro::log_printf(RETRO_LOG_DEBUG, "VM memory reallocation changed memory capacity from %llu bytes to %llu bytes\n", memory->capacity, (uint64_t)new_capacity);
uint8_t *new_private_data = (uint8_t *)std::realloc(memory->private_data, new_capacity);
if (new_private_data == nullptr) {
return -1;