Re: [netdev/net][ppc][bisected 8550ff8] build fails net/core/dev.c:6020:19: error: dereferencing pointer

From: Roi Dayan
Date: Thu Jul 08 2021 - 10:16:31 EST




On 2021-07-08 9:29 AM, Abdul Haleem wrote:
Greetings

netdev's net branch fails to build on my PowerPC box with error

net/core/dev.c: In function 'gro_list_prepare':
net/core/dev.c:6015:51: error: 'TC_SKB_EXT' undeclared (first use in this function); did you mean 'TC_U32_EAT'?
struct tc_skb_ext *skb_ext = skb_ext_find(skb, TC_SKB_EXT);
^~~~~~~~~~
TC_U32_EAT
net/core/dev.c:6015:51: note: each undeclared identifier is reported only once for each function it appears in
net/core/dev.c:6020:19: error: dereferencing pointer to incomplete type 'struct tc_skb_ext'
diffs |= p_ext->chain ^ skb_ext->chain;
^~
make[2]: *** [scripts/Makefile.build:273: net/core/dev.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [scripts/Makefile.build:516: net/core] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1847: net] Error 2
make: *** Waiting for unfinished jobs...

Which was included due to below commit

commit 8550ff8d8c75416e984d9c4b082845e57e560984
Author: Paul Blakey <paulb@xxxxxxxxxx <mailto:paulb@xxxxxxxxxx>>
Date: Mon Jul 5 13:54:51 2021 +0300

skbuff: Release nfct refcount on napi stolen or re-used skbs
When multiple SKBs are merged to a new skb under napi GRO,
or SKB is re-used by napi, if nfct was set for them in the
driver, it will not be released while freeing their stolen
head state or on re-use.
Release nfct on napi's stolen or re-used SKBs, and
in gro_list_prepare, check conntrack metadata diff.
Fixes: 5c6b94604744 ("net/mlx5e: CT: Handle misses after executing CT action")
Reviewed-by: Roi Dayan <roid@xxxxxxxxxx <mailto:roid@xxxxxxxxxx>>
Signed-off-by: Paul Blakey <paulb@xxxxxxxxxx <mailto:paulb@xxxxxxxxxx>>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx <mailto:davem@xxxxxxxxxxxxx>>

diff --git a/net/core/dev.c b/net/core/dev.c
index c253c2aafe97..177a5aec0b6b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6008,6 +6008,18 @@ static void gro_list_prepare(const struct list_head *head,
diffs = memcmp(skb_mac_header(p),
skb_mac_header(skb),
maclen);
+
+ diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb);
+
+ if (!diffs) {
+ struct tc_skb_ext *skb_ext = skb_ext_find(skb, TC_SKB_EXT);
+ struct tc_skb_ext *p_ext = skb_ext_find(p, TC_SKB_EXT);
+
+ diffs |= (!!p_ext) ^ (!!skb_ext);
+ if (!diffs && unlikely(skb_ext))
+ diffs |= p_ext->chain ^ skb_ext->chain;
+ }
+
NAPI_GRO_CB(p)->same_flow = !diffs;
}
}

kernel config is attached

@paul, could you please have a look into this ?

--
Regard's

Abdul Haleem
IBM Linux Technology Center


Hi,

This looks the same reason as Floarian fixed,
missing CONFIG_SKB_EXTENSIONS and CONFIG_NET_TC_SKB_EXT.
Fix was sent by Floarian titled "[PATCH net] skbuff: Fix build with SKB extensions disabled".

Thanks,
Roi