linux-kernel - Re: [PATCH] platform: uv: fix missing checks for kcalloc

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Message-ID: <20190325125528.GM12016@zn.tnic>
Date:   Mon, 25 Mar 2019 13:55:28 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Kangjie Lu <kjlu@....edu>
Cc:     pakki001@....edu, Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Mike Travis <mike.travis@....com>,
        Kees Cook <keescook@...omium.org>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Varsha Rao <rvarsha016@...il.com>,
        Nicolai Stange <nstange@...e.de>,
        Andrew Banman <abanman@....com>,
        Colin Ian King <colin.king@...onical.com>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform: uv: fix missing checks for kcalloc

On Sun, Mar 24, 2019 at 05:57:53PM -0500, Kangjie Lu wrote:
> In case kcalloc fails, the patch return an error to avoid
> potential NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@....edu>
> ---
>  arch/x86/platform/uv/tlb_uv.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
> index 2c53b0f19329..1ac777f14846 100644
> --- a/arch/x86/platform/uv/tlb_uv.c
> +++ b/arch/x86/platform/uv/tlb_uv.c
> @@ -2140,7 +2140,13 @@ static int __init init_per_cpu(int nuvhubs, int base_part_pnode)
>  		timeout_us = calculate_destination_timeout();
>  
>  	uvhub_descs = kcalloc(nuvhubs, sizeof(struct uvhub_desc), GFP_KERNEL);
> +	if (!uvhub_descs)
> +		return 1;

Here...

>  	uvhub_mask = kzalloc((nuvhubs+7)/8, GFP_KERNEL);
> +	if (!uvhub_mask) {
> +		kfree(uvhub_descs);
> +		return 1;
> +	}

... and here you can simply do

		goto fail;

instead. After having initialized uvhub_descs and uvhub_mask to NULL;

Thx.

-- 
Regards/Gruss,
    Boris.

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