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From:   Pintu Kumar <pintu.ping@gmail.com>
Date:   Fri, 6 Apr 2018 23:12:01 +0530
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Subject: Re: [PATCH v2] selftests/android/ion: fix heap_type may be uninitialized
To:     Anders Roxell <anders.roxell@linaro.org>
Cc:     Shuah Khan <shuah@kernel.org>, linux-kselftest@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>
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On Thu, Apr 5, 2018 at 1:09 PM, Anders Roxell <anders.roxell@linaro.org> wr=
ote:
> gcc warns that 'heap_type' is not initialized if we don't come through
> any of the two 'case' statesments before:
>
> ionapp_export.c:91:2: warning: =E2=80=98heap_type=E2=80=99 may be used un=
initialized in
> this function [-Wmaybe-uninitialized]
>   printf("heap_type: %ld, heap_size: %ld\n", heap_type, heap_size);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> In the current code, we initialize the heap_type to -1 before the 'case'
> statements. We also change the print_usage function to state that
> heap_type and heap_size isn't optional, they are mandatory.
>
> Fixes: 47a18c42d992 ("android/ion: userspace test utility for ion buffer =
sharing")
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
>  tools/testing/selftests/android/ion/ionapp_export.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/tools/testing/selftests/android/ion/ionapp_export.c b/tools/=
testing/selftests/android/ion/ionapp_export.c
> index a944e72621a9..67a0263a7f28 100644
> --- a/tools/testing/selftests/android/ion/ionapp_export.c
> +++ b/tools/testing/selftests/android/ion/ionapp_export.c
> @@ -31,8 +31,10 @@
>
>  void print_usage(int argc, char *argv[])
>  {
> -       printf("Usage: %s [-h <help>] [-i <heap id>] [-s <size in bytes>]=
\n",
> +       printf("Usage: %s [-h <help>] -i <heap id> -s <size in bytes>\n",
>                 argv[0]);
> +       printf("    Supported heap id's 0 or 1\n");
> +       printf("    Heap size > 0\n");
>  }
>
>  int main(int argc, char *argv[])
> @@ -40,7 +42,8 @@ int main(int argc, char *argv[])
>         int opt, ret, status, heapid;
>         int sockfd, client_fd, shared_fd;
>         unsigned char *map_buf;
> -       unsigned long map_len, heap_type, heap_size, flags;
> +       unsigned long map_len, heap_size, flags;
> +       long heap_type;
>         struct ion_buffer_info info;
>         struct socket_info skinfo;
>
> @@ -50,6 +53,7 @@ int main(int argc, char *argv[])
>         }
>
>         heap_size =3D 0;
> +       heap_type =3D -1;
>         flags =3D 0;
>

To make it simple, I would suggest, let the default heap_type be 0.
Actually that was my original intention but I would have missed it
during submission.
In that case nothing below is required to change.

>         while ((opt =3D getopt(argc, argv, "hi:s:")) !=3D -1) {
> @@ -68,7 +72,7 @@ int main(int argc, char *argv[])
>                                 heap_type =3D ION_HEAP_TYPE_SYSTEM_CONTIG=
;
>                                 break;
>                         default:
> -                               printf("ERROR: heap type not supported\n"=
);
> +                               print_usage(argc, argv);
>                                 exit(1);
>                         }
>                         break;
> @@ -82,8 +86,7 @@ int main(int argc, char *argv[])
>                 }
>         }
>
> -       if (heap_size <=3D 0) {
> -               printf("heap_size cannot be 0\n");
> +       if (heap_size <=3D 0 || heap_type < 0) {
>                 print_usage(argc, argv);
>                 exit(1);
>         }
> --
> 2.11.0
>