linux-kernel - Re: [PATCH] elf: fix "start

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Date:   Thu, 23 May 2019 11:44:17 -0700
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH] elf: fix "start_code" evaluation

On Thu, 23 May 2019 20:57:36 +0300 Alexey Dobriyan <adobriyan@...il.com> wrote:

> Only executable ELF program headers should change ->start_code.
> 
> ...
>
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -1026,7 +1026,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
>  			}
>  		}
>  		k = elf_ppnt->p_vaddr;
> -		if (k < start_code)
> +		if ((elf_ppnt->p_flags & PF_X) && k < start_code)
>  			start_code = k;
>  		if (start_data < k)
>  			start_data = k;

What problem does this solve?  How does it alter runtime behaviour? 
How do we know it won't break anything?