From: Willem de Bruijn <willemb@google.com>
Date: Wed, 20 Dec 2017 22:37:50 +0000 (-0500)
Subject: skbuff: skb_copy_ubufs must release uarg even without user frags
X-Git-Tag: v5.15~9760^2^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b90ddd568792bcb0054eaf0f61785c8f80c3bd1c;p=platform%2Fkernel%2Flinux-starfive.git

skbuff: skb_copy_ubufs must release uarg even without user frags

skb_copy_ubufs creates a private copy of frags[] to release its hold
on user frags, then calls uarg->callback to notify the owner.

Call uarg->callback even when no frags exist. This edge case can
happen when zerocopy_sg_from_iter finds enough room in skb_headlen
to copy all the data.

Fixes: 3ece782693c4 ("sock: skb_copy_ubufs support for compound pages")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index edf40ac0cd07..a3cb0be4c6f3 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1178,7 +1178,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 	u32 d_off;
 
 	if (!num_frags)
-		return 0;
+		goto release;
 
 	if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
 		return -EINVAL;
@@ -1238,6 +1238,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 	__skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off);
 	skb_shinfo(skb)->nr_frags = new_frags;
 
+release:
 	skb_zcopy_clear(skb, false);
 	return 0;
 }