Applied. Thanks! Regards, Jann > -----Ursprüngliche Nachricht----- > Von: Jarek Poplawski [mailto:[EMAIL PROTECTED] > Gesendet: Sonntag, 24. Februar 2008 20:51 > An: Jann Traschewski > Cc: netdev@vger.kernel.org; 'Ralf Baechle' > Betreff: Re: [BUG][AX25] spinlock lockup > > On Sun, Feb 24, 2008 at 04:10:29AM +0100, Jann Traschewski wrote: > > Hello, > > Hi! > > > I got a "spinlock lockup" using the latest Kernel 2.6.24.2 > with recent > > patches from Jarek Poplawski applied. > ... > > ppp_deflate nf_nat zlib_deflateBUG: unable to handle kernel NULL > > pointer dereference zlib_inflate nf_conntrack_ipv4 bsd_comp slhc > > ppp_async xt_state > ... > > EIP is at skb_append+0x1b/0x30 > ... > > 00000010 BUG: spinlock lockup on CPU#1, bcm/12213, f40846b8 > > Looks like 2 in 1: NULL pointer dereference and (later?) lockup. > > There is only one function in AX25 calling skb_append(), and > it really looks suspicious: appends skb after previously > enqueued one, but in the meantime this previous skb could be > removed from the queue. > > Here is a patch for testing: it fixes this simple way, so > this is not fully compatible with the current method, but > let's check if this could be a problem? > > Regards, > Jarek P. > > (testing patch #1) > > --- > > net/ax25/ax25_subr.c | 11 +++-------- > 1 files changed, 3 insertions(+), 8 deletions(-) > > diff --git a/net/ax25/ax25_subr.c b/net/ax25/ax25_subr.c > index d8f2157..034aa10 100644 > --- a/net/ax25/ax25_subr.c > +++ b/net/ax25/ax25_subr.c > @@ -64,20 +64,15 @@ void ax25_frames_acked(ax25_cb *ax25, > unsigned short nr) > > void ax25_requeue_frames(ax25_cb *ax25) { > - struct sk_buff *skb, *skb_prev = NULL; > + struct sk_buff *skb; > > /* > * Requeue all the un-ack-ed frames on the output queue > to be picked > * up by ax25_kick called from the timer. This > arrangement handles the > * possibility of an empty output queue. > */ > - while ((skb = skb_dequeue(&ax25->ack_queue)) != NULL) { > - if (skb_prev == NULL) > - skb_queue_head(&ax25->write_queue, skb); > - else > - skb_append(skb_prev, skb, &ax25->write_queue); > - skb_prev = skb; > - } > + while ((skb = skb_dequeue_tail(&ax25->ack_queue)) != NULL) > + skb_queue_head(&ax25->write_queue, skb); > } > > /*
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