From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ausmtp04.au.ibm.com (ausmtp04.au.ibm.com [202.81.18.152]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "ausmtp04.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 7C45067B6D for ; Mon, 16 Oct 2006 11:47:08 +1000 (EST) Received: from sd0109e.au.ibm.com (d23rh905.au.ibm.com [202.81.18.225]) by ausmtp04.au.ibm.com (8.13.8/8.13.5) with ESMTP id k9G1uNre249402 for ; Mon, 16 Oct 2006 11:56:24 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.250.242]) by sd0109e.au.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id k9G1o991089420 for ; Mon, 16 Oct 2006 11:50:09 +1000 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id k9G1khFa000349 for ; Mon, 16 Oct 2006 11:46:43 +1000 Date: Mon, 16 Oct 2006 11:43:34 +1000 From: David Gibson To: Yao Fei Zhu Subject: Re: Failed to boot kernel 2.6.19-rc2 due to IBM veth problem. Message-ID: <20061016014334.GA30921@localhost.localdomain> References: <4532613D.1090107@cn.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4532613D.1090107@cn.ibm.com> Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Oct 16, 2006 at 12:26:37AM +0800, Yao Fei Zhu wrote: > Hi, all, > > Boot kernel 2.6.19-rc2 on IBM System P5 partitions will fall into xmon. > Here is the boot log, This is probably the same bug I recently posted about. The patch below should fix it. ibmveth: Fix index increment calculation The recent commit 751ae21c6cd1493e3d0a4935b08fb298b9d89773 introduced a bug in the producer/consumer index calculation in the ibmveth driver - incautious use of the post-increment ++ operator resulted in an increment being immediately reverted. This patch corrects the logic. Without this patch, the driver oopses almost immediately after activation on at least some machines. Signed-off-by: David Gibson Index: working-2.6/drivers/net/ibmveth.c =================================================================== --- working-2.6.orig/drivers/net/ibmveth.c 2006-10-13 14:19:54.000000000 +1000 +++ working-2.6/drivers/net/ibmveth.c 2006-10-13 14:19:59.000000000 +1000 @@ -212,8 +212,8 @@ static void ibmveth_replenish_buffer_poo break; } - free_index = pool->consumer_index++ % pool->size; - pool->consumer_index = free_index; + free_index = pool->consumer_index; + pool->consumer_index = (pool->consumer_index + 1) % pool->size; index = pool->free_map[free_index]; ibmveth_assert(index != IBM_VETH_INVALID_MAP); @@ -329,8 +329,10 @@ static void ibmveth_remove_buffer_from_p adapter->rx_buff_pool[pool].buff_size, DMA_FROM_DEVICE); - free_index = adapter->rx_buff_pool[pool].producer_index++ % adapter->rx_buff_pool[pool].size; - adapter->rx_buff_pool[pool].producer_index = free_index; + free_index = adapter->rx_buff_pool[pool].producer_index; + adapter->rx_buff_pool[pool].producer_index + = (adapter->rx_buff_pool[pool].producer_index + 1) + % adapter->rx_buff_pool[pool].size; adapter->rx_buff_pool[pool].free_map[free_index] = index; mb(); -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson