Re: [Bugme-new] [Bug 38102] New: BUG kmalloc-2048: Poison overwritten

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mardi 05 juillet 2011 à 07:33 +0200, Eric Dumazet a écrit :
> Le mardi 05 juillet 2011 à 09:18 +0400, Alexey Zaytsev a écrit :
> 
> > Actually, I've added a trace to show b44_init_rings and b44_free_rings
> > calls, and they are only called once, right after the driver is
> > loaded. So it can't be related to START_RFO. Will attach the diff and
> > dmesg.
> 
> Thanks
> 
> I was wondering if DMA could be faster if providing word aligned
> addresses, could you try :
> 
> -#define RX_PKT_OFFSET          (RX_HEADER_LEN + 2)
> +#define RX_PKT_OFFSET          (RX_HEADER_LEN + NET_IP_ALIGN)
> 
> (On x86, we now have NET_IP_ALIGN = 0 since commit ea812ca1)
> 

I suspect a hardware bug.

You could force copybreak, so that b44 only touch kind of private
memory.

diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index a69331e..62a0599 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -75,7 +75,7 @@
 	  (BP)->tx_cons - (BP)->tx_prod - TX_RING_GAP(BP))
 #define NEXT_TX(N)		(((N) + 1) & (B44_TX_RING_SIZE - 1))
 
-#define RX_PKT_OFFSET		(RX_HEADER_LEN + 2)
+#define RX_PKT_OFFSET		(RX_HEADER_LEN + NET_IP_ALIGN)
 #define RX_PKT_BUF_SZ		(1536 + RX_PKT_OFFSET)
 
 /* minimum number of free TX descriptors required to wake up TX process */
@@ -829,6 +829,7 @@ static int b44_rx(struct b44 *bp, int budget)
 	}
 
 	bp->rx_cons = cons;
+	wmb();
 	bw32(bp, B44_DMARX_PTR, cons * sizeof(struct dma_desc));
 
 	return received;
@@ -848,6 +849,7 @@ static int b44_poll(struct napi_struct *napi, int budget)
 		/* spin_unlock(&bp->tx_lock); */
 	}
 	if (bp->istat & ISTAT_RFO) {	/* fast recovery, in ~20msec */
+		pr_err("b44: ISTAT_RFO !\n");
 		bp->istat &= ~ISTAT_RFO;
 		b44_disable_ints(bp);
 		ssb_device_enable(bp->sdev, 0); /* resets ISTAT_RFO */
@@ -2155,7 +2157,7 @@ static int __devinit b44_init_one(struct ssb_device *sdev,
 	bp = netdev_priv(dev);
 	bp->sdev = sdev;
 	bp->dev = dev;
-	bp->force_copybreak = 0;
+	bp->force_copybreak = 1;
 
 	bp->msg_enable = netif_msg_init(b44_debug, B44_DEF_MSG_ENABLE);