Re: [PATCH] gainfar.c : skb_over_panic (kernel-

From: Eran Liberty
Date: Mon Jun 28 2010 - 04:01:20 EST

David Miller wrote:
From: Eran Liberty <liberty@xxxxxxxxxxxx>
Date: Thu, 24 Jun 2010 12:53:23 +0300

Fix possible skb_over_panic event in Freescale's "gianfar" driver.

The skb_over_panic occurs due to calling skb_put() within
gfar_clean_rx_ring(). This happens if (and only if) shortly prior to
the event and a few lined above the skb_put(), an skb was queued back
to the priv->rx_recycle queue due to RXBD_LAST or RXBD_ERR status.
The skb is queued without properly re-setting its state.

The patch properly reset the skb state.

I have tested this patch on MPC8548 based product and asserted it
avoided the skb_over_panic event.

Signed-off-by: Eran Liberty <liberty@xxxxxxxxxxxx>

Eran, this seems to be fixed already. The code in the current
tree now reads:

* We need to un-reserve() the skb to what it
* was before gfar_new_skb() re-aligned
* it to an RXBUF_ALIGNMENT boundary
* before we put the skb back on the
* recycle list.
skb_reserve(skb, -GFAR_CB(skb)->alignamount);
__skb_queue_head(&priv->rx_recycle, skb);

This code has proved to be insufficient and produce skb_over_panic. The proposed patch fix this.

-- Liberty

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at