netdev - [PATCH] IPoIB: fix skb truesize underestimatiom

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1341950621.3265.6331.camel@edumazet-glaptop>
Date:	Tue, 10 Jul 2012 22:03:41 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	Or Gerlitz <ogerlitz@...lanox.com>,
	Erez Shitrit <erezsh@...lanox.com>,
	Roland Dreier <roland@...estorage.com>,
	netdev <netdev@...r.kernel.org>,
	Shlomo Pongartz <shlomop@...lanox.com>
Subject: [PATCH] IPoIB: fix skb truesize underestimatiom

From: Eric Dumazet <edumazet@...gle.com>

Or Gerlitz reported triggering of WARN_ON_ONCE(delta < len); in
skb_try_coalesce()
This warning tracks drivers that incorrectly set skb->truesize

IPoIB indeed allocates a full page to store a fragment, but only
accounts in skb->truesize the used part of the page (frame length)

This patch fixes skb truesize underestimation, and
also fixes a performance issue, because RX skbs have not enough tailroom
to allow IP and TCP stacks to pull their header in skb linear part
without an expensive call to pskb_expand_head()

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: Or Gerlitz <ogerlitz@...lanox.com>
Cc: Erez Shitrit <erezsh@...lanox.com>
Cc: Shlomo Pongartz <shlomop@...lanox.com>
Cc: Roland Dreier <roland@...estorage.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_ib.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 5c1bc99..f10221f 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -123,7 +123,7 @@ static void ipoib_ud_skb_put_frags(struct ipoib_dev_priv *priv,
 
 		skb_frag_size_set(frag, size);
 		skb->data_len += size;
-		skb->truesize += size;
+		skb->truesize += PAGE_SIZE;
 	} else
 		skb_put(skb, length);
 
@@ -156,14 +156,18 @@ static struct sk_buff *ipoib_alloc_rx_skb(struct net_device *dev, int id)
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	struct sk_buff *skb;
 	int buf_size;
+	int tailroom;
 	u64 *mapping;
 
-	if (ipoib_ud_need_sg(priv->max_ib_mtu))
+	if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
 		buf_size = IPOIB_UD_HEAD_SIZE;
-	else
+		tailroom = 128; /* reserve some tailroom for IP/TCP headers */
+	} else {
 		buf_size = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);
+		tailroom = 0;
+	}
 
-	skb = dev_alloc_skb(buf_size + 4);
+	skb = dev_alloc_skb(buf_size + tailroom + 4);
 	if (unlikely(!skb))
 		return NULL;
 


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html