Subject: Re: [PATCH 5/5] [RFC] devlink: Fix uninitialized error code in devlink_fmsg_prepare_skb()

From: Jiri Pirko <[email-masked]>
Date: Wed, 29 May 2019 10:04:52 +0200

Tue, May 28, 2019 at 04:24:24PM CEST, [email-masked] wrote:
>With gcc 4.1:
>
>    net/core/devlink.c: In function ‘devlink_fmsg_prepare_skb’:
>    net/core/devlink.c:4325: warning: ‘err’ may be used uninitialized in this function
>
>Indeed, if the list has less than *start entries, an uninitialized error
>code will be returned.
>
>Fix this by preinitializing err to zero.
>
>Fixes: 1db64e8733f65381 ("devlink: Add devlink formatted message (fmsg) API")
>Signed-off-by: Geert Uytterhoeven <[email-masked]>
>---
>I don't know if this can really happen, and if this is the right fix.
>Perhaps err should be initialized to some valid error code instead?

0 is correct here.
Acked-by: Jiri Pirko <[email-masked]>

Thanks!

>---
> net/core/devlink.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index d43bc52b8840d76b..91377e4eae9a43c1 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -4321,8 +4321,8 @@ devlink_fmsg_prepare_skb(struct devlink_fmsg *fmsg, struct sk_buff *skb,
> {
> 	struct devlink_fmsg_item *item;
> 	struct nlattr *fmsg_nlattr;
>+	int err = 0;
> 	int i = 0;
>-	int err;
> 
> 	fmsg_nlattr = nla_nest_start_noflag(skb, DEVLINK_ATTR_FMSG);
> 	if (!fmsg_nlattr)
>-- 
>2.17.1
>