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authorJarek Poplawski <jarkao2@gmail.com>2008-02-18 09:31:19 +0300
committerDavid S. Miller <davem@davemloft.net>2008-02-18 09:31:19 +0300
commitf47b7257c7368698eabff6fd7b340071932af640 (patch)
treed3733ff661cda7c00478348293810b3aeec6a1af /net/ax25
parent9bf1d83e7ee653862ef740435a7f41e8fd6452a9 (diff)
downloadlinux-f47b7257c7368698eabff6fd7b340071932af640.tar.xz
[AX25] ax25_out: check skb for NULL in ax25_kick()
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>
Diffstat (limited to 'net/ax25')
-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) {