Re: [Xen-devel] [PATCH v8 04/16] microcode/amd: fix memory leak

[Jan Beulich <JBeulich@xxxxxxxx>]

On 01.08.2019 12:22, Chao Gao wrote:
> --- a/xen/arch/x86/microcode_amd.c
> +++ b/xen/arch/x86/microcode_amd.c
> @@ -433,6 +433,9 @@ static int cpu_request_microcode(unsigned int cpu, const 
> void *buf,
>           goto out;
>       }
>   
> +    mc_amd->equiv_cpu_table_size = 0;
> +    mc_amd->equiv_cpu_table = NULL;

Instead of adding these, you could as well use xzalloc()
further up and drop the explicit initialization of ->mpb and
->mpb_size to NULL/0 a few lines down.

> @@ -479,6 +482,8 @@ static int cpu_request_microcode(unsigned int cpu, const 
> void *buf,
>   
>       if ( error )
>       {
> +        if ( mc_amd->equiv_cpu_table_size )
> +            xfree(mc_amd->equiv_cpu_table);

Why the if()? There's no problem calling xfree() with a NULL
argument.

> @@ -549,11 +554,14 @@ static int cpu_request_microcode(unsigned int cpu, 
> const void *buf,
>   
>       if ( save_error )
>       {
> -        xfree(mc_amd);
>           uci->mc.mc_amd = mc_old;
> +        mc_old = mc_amd;
>       }
> -    else
> -        xfree(mc_old);
> +
> +    if ( mc_old->mpb_size )
> +        xfree(mc_old->mpb);
> +    xfree(mc_old->equiv_cpu_table);

Same here. With the adjustments made (could possibly be done
again while committing)
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan
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