[jdk11u-dev] Withdrawn: 8367766: [11u] src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:321:3: error: 'tmp.dp' may be used uninitialized

[duke]

On Tue, 16 Sep 2025 16:23:09 GMT, Zdenek Zambersky <zzambers at openjdk.org> wrote:

> This error/warning has been seen on newer gcc versions on openjdk 11: 
> 
> In function 'mp_zero',
>     inlined from 'mp_zero' at /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:316:8,
>     inlined from 'mp_set_int' at /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:353:3,
>     inlined from 'mp_cmp_int' at /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:1735:26:
> /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:321:3: error: 'tmp.dp' may be used uninitialized [-Werror=maybe-uninitialized]
>   321 |   s_mp_setz(DIGITS(mp), ALLOC(mp));
>       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c: In function 'mp_cmp_int':
> /home/tester/temurinbuild-1757944128/workspace/build/src/src/jdk.crypto.ec/share/native/libsunec/impl/mpi.c:1730:11: note: 'tmp' declared here
>  1730 |   mp_int  tmp;
>       |           ^~~
> 
> 
> Problem does not affect newer jdks, because affected code was removed by [JDK-8235710](https://bugs.openjdk.org/browse/JDK-8235710).
> 
> Also whether warning/error is generated depends on other conditions like compiler version / arch / build kind etc. Seems like compiler needs to do enough inlining to detect this, as analysis needs to cross function boundary.
> 
> **Details/Fix:**
> Underlining issue seems to be that `mp_init` called on `tmp` (struct) may theoretically fail, unitialized `tmp` would then still be passed to subsequent functions. Unfortunately `mp_cmp_int` is not really designed to be able to handle errors.
> 
> So I just zero initialize tmp, which makes error/warning go away. I think making more involved changes to API/implementation is probably not worth the effort, especially when code is for legacy curves, removed in newer jdks. It would also increase risk of regressions.

This pull request has been closed without being integrated.

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

PR: https://git.openjdk.org/jdk11u-dev/pull/3095