| Message ID | 20231117152728.2286551-1-chentao@kylinos.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ipv4: Correct/silence an endian warning in __ip_do_redirect | expand |
On Fri, Nov 17, 2023 at 6:07 PM Kunwu Chan <chentao@kylinos.cn> wrote: > > net/ipv4/route.c:783:46: warning: incorrect type in argument 2 (different base types) > net/ipv4/route.c:783:46: expected unsigned int [usertype] key > net/ipv4/route.c:783:46: got restricted __be32 [usertype] new_gw > > Signed-off-by: Kunwu Chan <chentao@kylinos.cn> We need Fixes: tag for networking patches. > --- > net/ipv4/route.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index 3290a4442b4a..e8a542c6b031 100644 > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -780,7 +780,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow > goto reject_redirect; > } > > - n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); > + n = __ipv4_neigh_lookup(rt->dst.dev, be32_to_cpu(new_gw)); > if (!n) > n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); > if (!IS_ERR(n)) { > -- > 2.34.1 > How was this patch tested ? You are 'fixing' sparse warnings by replacing them with real bugs. be32_to_cpu() is going to swap bytes on x86, so the lookup will fail horribly. Here, if you must silence sparse, you want (__force u32)new_gw Look at this commit for a template. commit 3c42b2019863b327caa233072c50739d4144dd16
Hi Eric,
Thank you so much for taking the time to guide me, I'm a rookie who
really wants to do my part for the kernel, and I can't get started, so I
thought about eliminating some of the sparse warnings. I've looked at
some other commits and thought I could resolve the alert this way, sorry
for the trouble.
Follow your suggestion:
1. I will add a 'Fixes' tag as follows:
'Fixes: 969447f226b4 ("ipv4: use new_gw for redirect neigh lookup")'
2. Refer to the modification method of commit
3c42b2019863b327caa233072c50739d4144dd16, and modify the patch to:
'n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw); '
On 2023/11/18 01:15, Eric Dumazet wrote:
> On Fri, Nov 17, 2023 at 6:07 PM Kunwu Chan <chentao@kylinos.cn> wrote:
>>
>> net/ipv4/route.c:783:46: warning: incorrect type in argument 2 (different base types)
>> net/ipv4/route.c:783:46: expected unsigned int [usertype] key
>> net/ipv4/route.c:783:46: got restricted __be32 [usertype] new_gw
>>
>> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
>
> We need Fixes: tag for networking patches.
>
>> ---
>> net/ipv4/route.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
>> index 3290a4442b4a..e8a542c6b031 100644
>> --- a/net/ipv4/route.c
>> +++ b/net/ipv4/route.c
>> @@ -780,7 +780,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
>> goto reject_redirect;
>> }
>>
>> - n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
>> + n = __ipv4_neigh_lookup(rt->dst.dev, be32_to_cpu(new_gw));
>> if (!n)
>> n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
>> if (!IS_ERR(n)) {
>> --
>> 2.34.1
>>
>
> How was this patch tested ?
>
> You are 'fixing' sparse warnings by replacing them with real bugs.
>
> be32_to_cpu() is going to swap bytes on x86, so the lookup will fail horribly.
>
> Here, if you must silence sparse, you want (__force u32)new_gw
>
> Look at this commit for a template.
>
> commit 3c42b2019863b327caa233072c50739d4144dd16
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 3290a4442b4a..e8a542c6b031 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -780,7 +780,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow goto reject_redirect; } - n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); + n = __ipv4_neigh_lookup(rt->dst.dev, be32_to_cpu(new_gw)); if (!n) n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); if (!IS_ERR(n)) {
net/ipv4/route.c:783:46: warning: incorrect type in argument 2 (different base types) net/ipv4/route.c:783:46: expected unsigned int [usertype] key net/ipv4/route.c:783:46: got restricted __be32 [usertype] new_gw Signed-off-by: Kunwu Chan <chentao@kylinos.cn> --- net/ipv4/route.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)