Validating for memory leak issue

[gskrish7]

I am creating a JSON like this: { "msg":"type-a", "uid":"op01kd", "key":"9kasHmSmsQhhBXTk", "node-ctx":{ "id":"r111", "type":"safety", "auth-code":"269hdHE4NiruSZS4JnnckA==" }, "global-code":"9cM2b/WkVMgsHSPknmJrDMZiOc8B+cFh5XbXVjMH5yw=" }

When I use JSON library to create a new JSON object and add objects one by one and finally(after consuming JSON) free the object using cJSON_Delete()/ This system obviously occupies heap after some time and application exits as malloc fails. If I replace JSON operation with simple snprintf to construct JSON string manually, it is working fine. Is there any memory leak on version 1.7.10? Could we validate the library for memory leak check with tool like valgrind?

[mbratch]

Show your code. I suspect you may not be freeing the cJSON resources properly.

[gskrish7]

Sure, after adding elements; do I need to free node objects individually or does cJSON_Delete(root) will delete everything?

[mbratch]

If you are adding elements under root and you didn't "detach" any of them, then freeing root should free everything in the element tree.

To do a more complete assessment, source code snippet would be needed.

On Mar 4, 2022, 7:06 AM, at 7:06 AM, gskrish7 @.***> wrote:

Sure, after adding elements; do I need to free node object individually or does cJSON_Delete(root) will delete everything?

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[zepthro]

@gskrish7 I tried something locally, and I suspect like @mbratch, that you may be failing to free some external resource.

Are you printing the object? If you call cJSON_Print(root), malloc is used. Be sure to free the string that cJSON_Print returns.

static void create_objects(void)
{
    cJSON *root = NULL;
    cJSON *fmt = NULL;

    root = cJSON_CreateObject();
    cJSON_AddStringToObject(root, "msg", "type-a");
    cJSON_AddStringToObject(root, "uid", "op01kd");
    cJSON_AddStringToObject(root, "key", "9kasHmSmsQhhBXTk");

    cJSON_AddItemToObject(root, "node-ctx", fmt = cJSON_CreateObject());

    cJSON_AddStringToObject(fmt, "id", "r111");
    cJSON_AddStringToObject(fmt, "type", "safety");
    cJSON_AddStringToObject(fmt, "auth-code", "269hdHE4NiruSZS4JnnckA==");
    cJSON_AddStringToObject(root, "global-code", "9cM2b/WkVMgsHSPknmJrDMZiOc8B+cFh5XbXVjMH5yw=");
    
    cJSON_Delete(root);
}

---

==2806== HEAP SUMMARY:
==2806==     in use at exit: 0 bytes in 0 blocks
==2806==   total heap usage: 25 allocs, 25 frees, 4,836 bytes allocated
==2806==
==2806== All heap blocks were freed -- no leaks are possible