From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Subject: Re: [PATCH v2] efi: fix handling error value in fdt_find_uefi_params
Date: Mon, 5 Sep 2016 11:27:23 +0100
Message-ID: <20160905102723.GB32579@codeblueprint.co.uk>
References: <20160830100742.GA32579@codeblueprint.co.uk>
 <1472553697-27984-1-git-send-email-a.hajda@samsung.com>
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To: Andrzej Hajda <a.hajda-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Cc: "open list:EXTENSIBLE FIRMWARE INTERFACE (EFI)" <linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Bartlomiej Zolnierkiewicz <b.zolnierkie-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, "H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, Shawn Lin <shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
List-Id: linux-efi@vger.kernel.org

On Tue, 30 Aug, at 12:41:37PM, Andrzej Hajda wrote:
> of_get_flat_dt_subnode_by_name can return negative value in case of error.
> Assigning the result to unsigned variable and checking if the variable
> is lesser than zero is incorrect and always false.
> The patch fixes it by using signed variable to check the result.
> 
> The problem has been detected using semantic patch
> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci
> 
> Signed-off-by: Andrzej Hajda <a.hajda-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>  drivers/firmware/efi/efi.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 5a2631a..7dd2e2d 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -657,9 +657,12 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
>  		}
>  
>  		if (subnode) {
> -			node = of_get_flat_dt_subnode_by_name(node, subnode);
> -			if (node < 0)
> +			int err = of_get_flat_dt_subnode_by_name(node, subnode);
> +
> +			if (err < 0)
>  				return 0;
> +
> +			node = err;
>  		}
>  
>  		return __find_uefi_params(node, info, dt_params[i].params);

Thanks Andrzej, applied.