RFR: 8282628: Potential memory leak in sun.font.FontConfigManager.getFontConfig()

[Sergey Bylokhov]

On Fri, 4 Mar 2022 13:25:12 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> Please review this small patch that fixes a potential memory leak that exception return fails to release allocated `cacheDirs`
> 
> Test:
> 
> - [x] jdk_desktop on Linux x86_64

src/java.desktop/unix/native/common/awt/fontpath.c line 938:

> 936:             while ((cnt < max) && (cacheDir = (*FcStrListNext)(cacheDirs))) {
> 937:                 jstr = (*env)->NewStringUTF(env, (const char*)cacheDir);
> 938:                 JNU_CHECK_EXCEPTION_AND_CLEANUP(env, (*FcStrListDone)(cacheDirs));

I think you do not need to create an additional macro here, just inline it and call "(*FcStrListDone)(cacheDirs);" directly. Something like:

if (IS_NULL(jstr) {
    (*FcStrListDone)(cacheDirs);
    return;
}

Note that the "IS_NULL" is used in this file after NewStringUTF. Any objections?

src/java.desktop/unix/native/common/awt/fontpath.c line 940:

> 938:                 JNU_CHECK_EXCEPTION_AND_CLEANUP(env, (*FcStrListDone)(cacheDirs));
> 939: 
> 940:                 (*env)->SetObjectArrayElement(env, cacheDirArray, cnt++, jstr);

Probably we should add the check+cleanup after the SetObjectArrayElement? Otherwise, we may call NewStringUTF while an exception is raised by the SetObjectArrayElement.

-------------

PR: https://git.openjdk.java.net/jdk/pull/7691