linux-kernel - Re: [patch] kexec: potetially using uninitialized variable

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Message-ID: <56E2875B.8010909@redhat.com>
Date:	Fri, 11 Mar 2016 16:52:43 +0800
From:	Xunlei Pang <xpang@...hat.com>
To:	Dan Carpenter <dan.carpenter@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Vivek Goyal <vgoyal@...hat.com>
Cc:	Dave Young <dyoung@...hat.com>, Xunlei Pang <xlpang@...hat.com>,
	Ingo Molnar <mingo@...nel.org>,
	Toshi Kani <toshi.kani@....com>,
	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Minfei Huang <mnfhuang@...il.com>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [patch] kexec: potetially using uninitialized variable

Hi Dan,

On 2016/03/11 at 16:07, Dan Carpenter wrote:
> At the end of the function we check if "ret" has a negative error code,
> but it seems possible that it is uninitialized.
>
> Fixes: 12db5562e035 ('kexec: load and relocate purgatory at kernel load time')
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
>
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 503bc2d..63d1af3 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -795,7 +795,7 @@ out:
>  
>  static int kexec_apply_relocations(struct kimage *image)
>  {
> -	int i, ret;
> +	int i, ret = 0;
>  	struct purgatory_info *pi = &image->purgatory_info;
>  	Elf_Shdr *sechdrs = pi->sechdrs;
>  

Look further, there is a condition at the beginning of the for loop:
 

        if (sechdrs[i].sh_type != SHT_RELA &&
            sechdrs[i].sh_type != SHT_REL)
            continue;

So, I think that's ok, but I don't konw if GCC is smart enough not to throw warnings.

Regards,
Xunlei