[PATCH] efi: fix the wrong check for the offset of subnode

[PATCH] efi: fix the wrong check for the offset of subnode

[Shawn Lin]

of_get_flat_dt_subnode_by_name return the offset of
the subnode, and we should check if it's valid. But
the original code use the unsigned type to check it,
which makes the we always get subnode successfully
even if returning -FDT_ERR_BADPATH etc. Let's fix it
by adding offset variable.

Suggested-by: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
Signed-off-by: Shawn Lin <shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
---

 drivers/firmware/efi/efi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 5a2631a..7a5964e 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -647,6 +647,7 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
 {
 	struct param_info *info = data;
 	int i;
+	int offset = node;
 
 	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
 		const char *subnode = dt_params[i].subnode;
@@ -657,12 +658,12 @@ 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)
+			offset = of_get_flat_dt_subnode_by_name(node, subnode);
+			if (offset < 0)
 				return 0;
 		}
 
-		return __find_uefi_params(node, info, dt_params[i].params);
+		return __find_uefi_params(offset, info, dt_params[i].params);
 	}
 
 	return 0;
-- 
2.3.7

Re: [PATCH] efi: fix the wrong check for the offset of subnode

[Matt Fleming]

(Cc'ing Mark and other folks)

On Wed, 24 Aug, at 10:18:10AM, Shawn Lin wrote:
> of_get_flat_dt_subnode_by_name return the offset of
> the subnode, and we should check if it's valid. But
> the original code use the unsigned type to check it,
> which makes the we always get subnode successfully
> even if returning -FDT_ERR_BADPATH etc. Let's fix it
> by adding offset variable.
> 
> Suggested-by: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
> Signed-off-by: Shawn Lin <shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
> ---
> 
>  drivers/firmware/efi/efi.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
 
There's already a patch queued up in the 'urgent' branch for this
issue,

  https://git.kernel.org/cgit/linux/kernel/git/mfleming/efi.git/commit/?h=urgent&id=b7453c7a235c597b44c365887e57e7c300e72bf0

If your patch is superior in some way please mention that in the patch
description.

> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 5a2631a..7a5964e 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -647,6 +647,7 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
>  {
>  	struct param_info *info = data;
>  	int i;
> +	int offset = node;
>  
>  	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
>  		const char *subnode = dt_params[i].subnode;
> @@ -657,12 +658,12 @@ 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)
> +			offset = of_get_flat_dt_subnode_by_name(node, subnode);
> +			if (offset < 0)
>  				return 0;
>  		}
>  
> -		return __find_uefi_params(node, info, dt_params[i].params);
> +		return __find_uefi_params(offset, info, dt_params[i].params);
>  	}
>  
>  	return 0;
> -- 
> 2.3.7
> 
> 
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