Hi,
Here is an "official" version of "testing patch #2" from this thread.
The only difference: ax25->vs is changed only after checking skb is
not NULL (plus a comment). IMHO it could be applied.
Thanks,
Jarek P.
---------------->
Subject: [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 <[EMAIL PROTECTED]>
Signed-off-by: Jarek Poplawski <[EMAIL PROTECTED]>
---
diff -Nurp 2.6.24-mm1-/net/ax25/ax25_out.c 2.6.24-mm1+/net/ax25/ax25_out.c
--- 2.6.24-mm1-/net/ax25/ax25_out.c 2008-01-24 22:58:37.000000000 +0000
+++ 2.6.24-mm1+/net/ax25/ax25_out.c 2008-02-13 10:43:50.000000000 +0000
@@ -117,6 +117,12 @@ void ax25_output(ax25_cb *ax25, int pacl
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) {
--
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