Commit f47b7257 authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
Browse files

[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: default avatarJann Traschewski <>
Signed-off-by: default avatarJarek Poplawski <>
Signed-off-by: default avatarDavid S. Miller <>
parent 9bf1d83e
......@@ -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) {
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)
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)
ax25->vs = start;
do {
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment