[PATCH 3.12 31/64] connector: bump skb->users before callback invocation

From: Jiri Slaby
Date: Thu Feb 11 2016 - 09:00:35 EST


From: Florian Westphal <fw@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

[ Upstream commit 55285bf09427c5abf43ee1d54e892f352092b1f1 ]

Dmitry reports memleak with syskaller program.
Problem is that connector bumps skb usecount but might not invoke callback.

So move skb_get to where we invoke the callback.

Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/connector/connector.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index fb1bad083aa9..12e737e0a5af 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -160,26 +160,21 @@ static int cn_call_callback(struct sk_buff *skb)
*
* It checks skb, netlink header and msg sizes, and calls callback helper.
*/
-static void cn_rx_skb(struct sk_buff *__skb)
+static void cn_rx_skb(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
- struct sk_buff *skb;
int len, err;

- skb = skb_get(__skb);
-
if (skb->len >= NLMSG_HDRLEN) {
nlh = nlmsg_hdr(skb);
len = nlmsg_len(nlh);

if (len < (int)sizeof(struct cn_msg) ||
skb->len < nlh->nlmsg_len ||
- len > CONNECTOR_MAX_MSG_SIZE) {
- kfree_skb(skb);
+ len > CONNECTOR_MAX_MSG_SIZE)
return;
- }

- err = cn_call_callback(skb);
+ err = cn_call_callback(skb_get(skb));
if (err < 0)
kfree_skb(skb);
}
--
2.7.1