I've just tested the patch posted in bugzilla: it works.
That is, I do not manage to get the warning anymore in 3 boots in a row.
CC
Le mercredi 28 octobre 2009 20:05:47, John W. Linville a écrit :
> Christian,
>
> Will you be able to test this patch for us?
>
> Thanks,
>
> John
>
> On Mon, Oct 26, 2009 at 09:38:28PM +0100, Michael Buesch wrote:
> > On Monday 26 October 2009 20:37:33 Michael Buesch wrote:
> > > Ok, it just turns out this actually is a driver bug.
> > > Thanks to Johannes Berg for tracking it down.
> > >
> > > I think it's caused by the DMA bouncebuffer stuff that does not copy
> > > the skb->cb and does not adjust the "tx-info" pointer.
> > > I wonder why this didn't blow up easlier, because this bug is there
> > > since mac80211 switched to using the CB.
> > >
> > > Here's a completely untested patch.
> >
> > Here's a new version of the patch that also fixes queue mapping bugs:
> >
> > ---
> > drivers/net/wireless/b43/dma.c | 15 +++++++++++++--
> > 1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > --- wireless-testing.orig/drivers/net/wireless/b43/dma.c
> > +++ wireless-testing/drivers/net/wireless/b43/dma.c
> > @@ -1157,8 +1157,9 @@ struct b43_dmaring *parse_cookie(struct
> > }
> >
> > static int dma_tx_fragment(struct b43_dmaring *ring,
> > - struct sk_buff *skb)
> > + struct sk_buff **in_skb)
> > {
> > + struct sk_buff *skb = *in_skb;
> > const struct b43_dma_ops *ops = ring->ops;
> > struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
> > u8 *header;
> > @@ -1224,8 +1225,14 @@ static int dma_tx_fragment(struct b43_dm
> > }
> >
> > memcpy(skb_put(bounce_skb, skb->len), skb->data, skb->len);
> > + memcpy(bounce_skb->cb, skb->cb, sizeof(skb->cb));
> > + bounce_skb->dev = skb->dev;
> > + skb_set_queue_mapping(bounce_skb, skb_get_queue_mapping(skb));
> > + info = IEEE80211_SKB_CB(bounce_skb);
> > +
> > dev_kfree_skb_any(skb);
> > skb = bounce_skb;
> > + *in_skb = bounce_skb;
> > meta->skb = skb;
> > meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
> > if (b43_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
> > @@ -1355,7 +1362,11 @@ int b43_dma_tx(struct b43_wldev *dev, st
> > * static, so we don't need to store it per frame. */
> > ring->queue_prio = skb_get_queue_mapping(skb);
> >
> > - err = dma_tx_fragment(ring, skb);
> > + /* dma_tx_fragment might reallocate the skb, so invalidate pointers
> > pointing + * into the skb data or cb now. */
> > + hdr = NULL;
> > + info = NULL;
> > + err = dma_tx_fragment(ring, &skb);
> > if (unlikely(err == -ENOKEY)) {
> > /* Drop this packet, as we don't have the encryption key
> > * anymore and must not transmit it unencrypted. */
>
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