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authorJarek Poplawski <jarkao2@gmail.com>2008-04-06 23:35:31 -0700
committerChris Wright <chrisw@sous-sol.org>2008-04-18 18:53:24 -0700
commit0003f278998a59e72784048d7484e4a998ceab3d (patch)
treef5da86022f20f739ce69dcfed4c9c3dfd9ddd26e
parentb245c3b43439c715e33b57ca9b663123812dd208 (diff)
AX25 ax25_out: check skb for NULL in ax25_kick()
Upstream commit: f47b7257c7368698eabff6fd7b340071932af640 According to some OOPS reports ax25_kick tries to clone NULL skbs sometimes. It looks like a race with ax25_clear_queues(). Probably there is no need to add more than a simple check for this yet. Another report suggested there are probably also cases where ax25 ->paclen == 0 can happen in ax25_output(); this wasn't confirmed during testing but let's leave this debugging check for some time. Reported-and-tested-by: Jann Traschewski <jann@gmx.de> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
-rw-r--r--net/ax25/ax25_out.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c
index 92b517af7260..bf706f83a5c9 100644
--- a/net/ax25/ax25_out.c
+++ b/net/ax25/ax25_out.c
@@ -117,6 +117,12 @@ void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
unsigned char *p;
int frontlen, len, fragno, ka9qfrag, first = 1;
+ if (paclen < 16) {
+ WARN_ON_ONCE(1);
+ kfree_skb(skb);
+ return;
+ }
+
if ((skb->len - 1) > paclen) {
if (*skb->data == AX25_P_TEXT) {
skb_pull(skb, 1); /* skip PID */
@@ -251,8 +257,6 @@ void ax25_kick(ax25_cb *ax25)
if (start == end)
return;
- ax25->vs = start;
-
/*
* Transmit data until either we're out of data to send or
* the window is full. Send a poll on the final I frame if
@@ -261,8 +265,13 @@ void ax25_kick(ax25_cb *ax25)
/*
* Dequeue the frame and copy it.
+ * Check for race with ax25_clear_queues().
*/
skb = skb_dequeue(&ax25->write_queue);
+ if (!skb)
+ return;
+
+ ax25->vs = start;
do {
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {