[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[Aisheng.Dong]

Fec will crash when DMABOUNCE is enabled.
Unable to handle kernel NULL pointer dereference at virtual address 000000bc
pgd = 80004000
[000000bc] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT
last sysfs file:
Modules linked in:
CPU: 0    Not tainted  (2.6.35.3-00845-g204c152-dirty #112)
PC is at dma_map_single+0x2c/0x2a0
LR is at fec_enet_interrupt+0x1d4/0x450

The reason is DMA API of dmabounce needs the dev passed in is not NULL.

Here we'd always pass in a struct device if there is one available
for using DMA API to improve the code robustness sicne it may not
always work when passing a NULL dev.

Signed-off-by: Aisheng.Dong <b29396@freescale.com>
---
 drivers/net/fec.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index cd0282d..89a2ba4 100644
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -527,7 +527,7 @@ fec_enet_rx(struct net_device *dev)
 		dev->stats.rx_bytes += pkt_len;
 		data = (__u8*)__va(bdp->cbd_bufaddr);
 
-	        dma_unmap_single(NULL, bdp->cbd_bufaddr, bdp->cbd_datlen,
+		dma_unmap_single(&dev->dev, bdp->cbd_bufaddr, bdp->cbd_datlen,
         			DMA_FROM_DEVICE);
 
 		if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
@@ -552,7 +552,7 @@ fec_enet_rx(struct net_device *dev)
 			netif_rx(skb);
 		}
 
-        	bdp->cbd_bufaddr = dma_map_single(NULL, data, bdp->cbd_datlen,
+		bdp->cbd_bufaddr = dma_map_single(&dev->dev, data, bdp->cbd_datlen,
 			DMA_FROM_DEVICE);
 rx_processing_done:
 		/* Clear the status flags for this buffer */
-- 
1.7.0.4

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[David Miller]

First, your patches never make it to the mailing list because the list
server rejects your postings, due to the fact that there are syntax
errors in your email headers:

Illegal-Object:	Syntax error in From: address found on vger.kernel.org:
	From:	Aisheng.Dong<b29396@freescale.com>
				    ^-missing end of mailbox

Second, this patch does not apply to the current tree at all.
This bug has already been fixed and there are no cases where
a NULL device is passed to the DMA API interfaces any more.

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[Shawn Guo]

Hi David,

On Sat, Apr 02, 2011 at 12:57:14AM -0700, David Miller wrote:
> 
> First, your patches never make it to the mailing list because the list
> server rejects your postings, due to the fact that there are syntax
> errors in your email headers:
> 
> Illegal-Object:	Syntax error in From: address found on vger.kernel.org:
> 	From:	Aisheng.Dong<b29396@freescale.com>
> 				    ^-missing end of mailbox
> 
Yes, we were aware of that the mail did not get distributed by vger
list.  But we do not know why.  Thanks for telling.

I'm not quite sure about the "^" indication.  Is it telling that there
should be a space between display name and mail address?

-- 
Regards,
Shawn

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[David Miller]

From: Shawn Guo <shawn.guo@freescale.com>
Date: Sat, 2 Apr 2011 16:31:32 +0800

> I'm not quite sure about the "^" indication.  Is it telling that there
> should be a space between display name and mail address?

Yes.

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[Jason Liu]

2011/4/2 Shawn Guo <shawn.guo@freescale.com>:
> Hi David,
>
> On Sat, Apr 02, 2011 at 12:57:14AM -0700, David Miller wrote:
>>
>> First, your patches never make it to the mailing list because the list
>> server rejects your postings, due to the fact that there are syntax
>> errors in your email headers:
>>
>> Illegal-Object: ? ? ? Syntax error in From: address found on vger.kernel.org:
>> ? ? ? From: ? Aisheng.Dong<b29396@freescale.com>
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^-missing end of mailbox
>>
> Yes, we were aware of that the mail did not get distributed by vger
> list. ?But we do not know why. ?Thanks for telling.
>
> I'm not quite sure about the "^" indication. ?Is it telling that there
> should be a space between display name and mail address?

We should not use A.B <>, instead should use A B <>.

Jason

>
> --
> Regards,
> Shawn
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[David Miller]

From: Jason Liu <liu.h.jason@gmail.com>
Date: Sat, 2 Apr 2011 16:35:19 +0800

> 2011/4/2 Shawn Guo <shawn.guo@freescale.com>:
>> Hi David,
>>
>> On Sat, Apr 02, 2011 at 12:57:14AM -0700, David Miller wrote:
>>>
>>> First, your patches never make it to the mailing list because the list
>>> server rejects your postings, due to the fact that there are syntax
>>> errors in your email headers:
>>>
>>> Illegal-Object: ? ? ? Syntax error in From: address found on vger.kernel.org:
>>> ? ? ? From: ? Aisheng.Dong<b29396@freescale.com>
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^-missing end of mailbox
>>>
>> Yes, we were aware of that the mail did not get distributed by vger
>> list. ?But we do not know why. ?Thanks for telling.
>>
>> I'm not quite sure about the "^" indication. ?Is it telling that there
>> should be a space between display name and mail address?
> 
> We should not use A.B <>, instead should use A B <>.

Yes, this is also true.

Characters such as "." must not appear in email headers in this
context unless protected by double quotes.

[PATCH 1/1] net/fec: do not pass NULL dev to DMA API

[Dong Aisheng-B29396]

> -----Original Message-----
> From: David Miller [mailto:davem at davemloft.net]
> Sent: Saturday, April 02, 2011 4:36 PM
> To: liu.h.jason at gmail.com
> Cc: Guo Shawn-R65073; netdev at vger.kernel.org; Dong Aisheng-B29396; linux-
> arm-kernel at lists.infradead.org
> Subject: Re: [PATCH 1/1] net/fec: do not pass NULL dev to DMA API
> 
> From: Jason Liu <liu.h.jason@gmail.com>
> Date: Sat, 2 Apr 2011 16:35:19 +0800
> 
> > 2011/4/2 Shawn Guo <shawn.guo@freescale.com>:
> >> Hi David,
> >>
> >> On Sat, Apr 02, 2011 at 12:57:14AM -0700, David Miller wrote:
> >>>
> >>> First, your patches never make it to the mailing list because the
> >>> list server rejects your postings, due to the fact that there are
> >>> syntax errors in your email headers:
> >>>
> >>> Illegal-Object: ? ? ? Syntax error in From: address found on
> vger.kernel.org:
> >>> ? ? ? From: ? Aisheng.Dong<b29396@freescale.com>
> >>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^-missing end of mailbox
> >>>
> >> Yes, we were aware of that the mail did not get distributed by vger
> >> list. ?But we do not know why. ?Thanks for telling.
> >>
> >> I'm not quite sure about the "^" indication. ?Is it telling that
> >> there should be a space between display name and mail address?
> >
> > We should not use A.B <>, instead should use A B <>.
> 
> Yes, this is also true.
> 
> Characters such as "." must not appear in email headers in this context
> unless protected by double quotes.
Thanks a lot David.
This issue has bothered me a lot and finally the root cause is found.

For the patch I just found it was already fixed in your 2.6.x -next tree.
Thanks for the info.

Regards
Aisheng