2.6.15-rc5 spits oodles of hw csum failures

2.6.15-rc5 spits oodles of hw csum failures

[Jens Axboe]

Hi,

Just booted -rc5 on another one of my boxes, and I get literally tons of
these everytime there's some network activity:

printk: 300 messages suppressed.
<NULL>: hw csum failure.

Call Trace: <IRQ> <ffffffff80357463>{__skb_checksum_complete+76}
       <ffffffff80381e89>{tcp_rcv_established+1384}
<ffffffff80388ee9>{tcp_v4_d}
       <ffffffff8038a4ee>{tcp_v4_rcv+2285}
<ffffffff8036f59f>{ip_local_deliver+}
       <ffffffff8036f480>{ip_rcv+1043}
<ffffffff8035bc0a>{netif_receive_skb+460}
       <ffffffff8035bd08>{process_backlog+142}
<ffffffff8035a8a5>{net_rx_action}
       <ffffffff8013641e>{__do_softirq+100}
<ffffffff8010ef9b>{call_softirq+31}
       <ffffffff8011028c>{do_softirq+44} <ffffffff801102c4>{do_IRQ+52}
       <ffffffff8010df9a>{ret_from_intr+0}  <EOI>
<ffffffff8010c4a3>{default_id}
       <ffffffff8010c547>{cpu_idle+97}
<ffffffff806327d5>{start_kernel+389}
       <ffffffff8063225e>{_sinittext+606} 

The box is using the sk98lin driver.

-- 
Jens Axboe

Re: 2.6.15-rc5 spits oodles of hw csum failures

[Stephen Hemminger]

You missed this patch that I posted just after Linus left for parts unknown.

Index: linux-2.6/drivers/net/sk98lin/skge.c
===================================================================
--- linux-2.6.orig/drivers/net/sk98lin/skge.c
+++ linux-2.6/drivers/net/sk98lin/skge.c
@@ -818,7 +818,7 @@ uintptr_t VNextDescr;	/* the virtual bus
 		/* set the pointers right */
 		pDescr->VNextRxd = VNextDescr & 0xffffffffULL;
 		pDescr->pNextRxd = pNextDescr;
-		pDescr->TcpSumStarts = 0;
+		if (!IsTx) pDescr->TcpSumStarts = ETH_HLEN << 16 | ETH_HLEN;
 
 		/* advance one step */
 		pPrevDescr = pDescr;
@@ -2169,7 +2169,7 @@ rx_start:	
 		} /* frame > SK_COPY_TRESHOLD */
 
 #ifdef USE_SK_RX_CHECKSUM
-		pMsg->csum = pRxd->TcpSums;
+		pMsg->csum = pRxd->TcpSums & 0xffff;
 		pMsg->ip_summed = CHECKSUM_HW;
 #else
 		pMsg->ip_summed = CHECKSUM_NONE;