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authorEric Dumazet <edumazet@google.com>2022-01-31 22:52:54 -0800
committerJakub Kicinski <kuba@kernel.org>2022-02-01 20:21:40 -0800
commit479f5547239d970d3833f15f54a6481fffdb91ec (patch)
tree524d5d9fedeea8d2594e0b7bdb9f524da541143a /net
parente42e70ad6ae2ae511a6143d2e8da929366e58bd9 (diff)
tcp: fix mem under-charging with zerocopy sendmsg()
We got reports of following warning in inet_sock_destruct() WARN_ON(sk_forward_alloc_get(sk)); Whenever we add a non zero-copy fragment to a pure zerocopy skb, we have to anticipate that whole skb->truesize will be uncharged when skb is finally freed. skb->data_len is the payload length. But the memory truesize estimated by __zerocopy_sg_from_iter() is page aligned. Fixes: 9b65b17db723 ("net: avoid double accounting for pure zerocopy skbs") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Talal Ahmad <talalahmad@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Link: https://lore.kernel.org/r/20220201065254.680532-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 78e81465f5f3..bdf108f544a4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1322,10 +1322,13 @@ new_segment:
/* skb changing from pure zc to mixed, must charge zc */
if (unlikely(skb_zcopy_pure(skb))) {
- if (!sk_wmem_schedule(sk, skb->data_len))
+ u32 extra = skb->truesize -
+ SKB_TRUESIZE(skb_end_offset(skb));
+
+ if (!sk_wmem_schedule(sk, extra))
goto wait_for_space;
- sk_mem_charge(sk, skb->data_len);
+ sk_mem_charge(sk, extra);
skb_shinfo(skb)->flags &= ~SKBFL_PURE_ZEROCOPY;
}