Re: Failed to boot kernel 2.6.19-rc2 due to IBM veth problem.

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David Gibson 写道:
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 <[email protected]>

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, I have verified this fix, it works fine for me, Thanks. What's the status of it? Submitted?

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