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fix: Protect mem consumption from null deref #4895

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fix: Protect mem consumption from null deref #4895

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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -44,3 +44,4 @@ samples/workload/include/**

tests/unit/runtime-common/wasm-apps/main.aot
tests/unit/aot-stack-frame/wasm-apps/test_aot.h
.worktrees/
20 changes: 20 additions & 0 deletions core/iwasm/aot/aot_runtime.c
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Expand Up @@ -966,6 +966,7 @@ memories_deinstantiate(AOTModuleInstance *module_inst)
}
}
wasm_runtime_free(module_inst->memories);
module_inst->memories = NULL;
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@TianlongLiang TianlongLiang Apr 17, 2026

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I don't think it's worth setting NULL here? Given the fact that the module instance will be destroyed later anyway?

}

static AOTMemoryInstance *
Expand Down Expand Up @@ -3795,13 +3796,32 @@ aot_get_module_mem_consumption(const AOTModule *module,
mem_conspn->total_size += mem_conspn->aot_code_size;
}

/**
* Calculate memory consumption of an AOT module instance.
*
* @param module_inst pointer to a fully initialized AOT module instance
* @param mem_conspn output structure to store memory consumption details
*
* @pre module_inst != NULL
* @pre module_inst->module != NULL
* @pre module_inst->e != NULL
* @pre (module_inst->memory_count == 0) || (module_inst->memories != NULL)
*
* In debug builds, these preconditions are validated with bh_assert.
* In release builds, violating preconditions results in undefined behavior.
*/
void
aot_get_module_inst_mem_consumption(const AOTModuleInstance *module_inst,
WASMModuleInstMemConsumption *mem_conspn)
{
AOTTableInstance *tbl_inst;
uint32 i;

bh_assert(module_inst);
bh_assert(module_inst->module);
bh_assert(module_inst->e);
bh_assert(!module_inst->memory_count || module_inst->memories);

memset(mem_conspn, 0, sizeof(*mem_conspn));

mem_conspn->module_inst_struct_size = sizeof(AOTModuleInstance);
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23 changes: 22 additions & 1 deletion core/iwasm/interpreter/wasm_runtime.c
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Expand Up @@ -3445,9 +3445,11 @@ wasm_deinstantiate(WASMModuleInstance *module_inst, bool is_sub_inst)
(WASMModuleInstanceCommon *)module_inst);
#endif

if (module_inst->memory_count > 0)
if (module_inst->memory_count > 0) {
memories_deinstantiate(module_inst, module_inst->memories,
module_inst->memory_count);
module_inst->memories = NULL;
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@TianlongLiang TianlongLiang Apr 17, 2026

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I don't think it's worth setting NULL here? Given the fact that this module inst is about to be destroyed anyway? It will create an inconsistency with other data members, like L3455

}

if (module_inst->import_func_ptrs) {
wasm_runtime_free(module_inst->import_func_ptrs);
Expand Down Expand Up @@ -4227,13 +4229,32 @@ wasm_get_module_mem_consumption(const WASMModule *module,
mem_conspn->total_size += mem_conspn->const_strs_size;
}

/**
* Calculate memory consumption of a WASM module instance.
*
* @param module_inst pointer to a fully initialized WASM module instance
* @param mem_conspn output structure to store memory consumption details
*
* @pre module_inst != NULL
* @pre module_inst->module != NULL
* @pre module_inst->e != NULL
* @pre (module_inst->memory_count == 0) || (module_inst->memories != NULL)
*
* In debug builds, these preconditions are validated with bh_assert.
* In release builds, violating preconditions results in undefined behavior.
*/
void
wasm_get_module_inst_mem_consumption(const WASMModuleInstance *module_inst,
WASMModuleInstMemConsumption *mem_conspn)
{
uint32 i;
uint64 size;

bh_assert(module_inst);
bh_assert(module_inst->module);
bh_assert(module_inst->e);
bh_assert(!module_inst->memory_count || module_inst->memories);

memset(mem_conspn, 0, sizeof(*mem_conspn));

mem_conspn->module_inst_struct_size = (uint8 *)module_inst->e
Expand Down
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