Hello all,
I have attached a small fix for the following problem:
When davinci_emac interface is down, changing MAC address results in
kernel oops, due to NULL pointer dereference.
I apologize for not inlining the patch into the message (since GMail
is the only web client I can use, and it does not allow me to inline
it correctly).
Remarks are welcomed.
Thanks in advance.
On Thu, Jun 25, 2009 at 11:31 AM, Nori, Sekhar<nsek...@ti.com> wrote:
>
> Pablo,
>
> Chaithrika's mails to gmail.com are bouncing, so I am replying
> on her behalf.
>
> "
> You are right there is indeed an issue. We looked at other
> drivers and found that this is solved by checking for netif_running
> to be true before going ahead and setting the mac address. Have a
> look at how this is done in tg3.c driver
>
> http://git.kernel.org/?p=linux/kernel/git/khilman/linux-davinci.git;a=blob;f=drivers/net/tg3.c;h=201be425643a6fb7acb8801bbbb718897c9a6431;hb=35265abf67337f57a023ffeae5f4c492e7f8ea24#l6589
> "
>
> Can you please go ahead and submit a fix for this to netdev
> mailing list and CC linux-davinci ML?
>
> Thanks,
> Sekhar
>
>> -----Original Message-----
>> From: Pablo Bitton [mailto:pablo.bit...@gmail.com]
>> Sent: Wednesday, June 24, 2009 7:13 PM
>> To: Subrahmanya, Chaithrika
>> Subject: A small fix to davinci_emac driver
>>
>> Hello,
>>
>> In drivers/net/davinci_emac.c file, at emac_dev_setmac_addr() function, rxch
>> is NULL when DaVinci EMAC is down (using "ifconfig eth0 down").
>>
>> So when MAC address is changed using "ifconfig eth0 hw ether
>> 00:11:22:33:44:55",
>> emac_dev_setmac_addr() performs an illegal access to rxch->mac_addr, which
>> causes a kernel oops.
>>
>> In order to fix this situation, the attached patch is applied (I've couldn't
>> inline it correctly into GMail).
>> Remarks are welcomed.
>>
>> Thanks in advance.
>
From ae9480af26eba3302614ea3d92077a80341cd190 Mon Sep 17 00:00:00 2001
From: Pablo Bitton <pablo.bit...@gmail.com>
Date: Tue, 23 Jun 2009 15:45:43 +0300
Subject: [PATCH] davinci_emac: fix kernel oops when changing MAC address while
interface is down
rxch == NULL when DaVinci EMAC is down (using "ifconfig eth0 down").
So when MAC address is changed using "ifconfig eth0 hw ether 00:11:22:33:44:55",
emac_dev_setmac_addr() performs an illegal access to rxch->mac_addr, which
causes a kernel oops.
Signed-off-by: Pablo Bitton <pablo.bit...@gmail.com>
---
drivers/net/davinci_emac.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
index cf689a0..cd114d9 100644
--- a/drivers/net/davinci_emac.c
+++ b/drivers/net/davinci_emac.c
@@ -1823,9 +1823,14 @@ static int emac_dev_setmac_addr(struct net_device *ndev,
void *addr)
/* Store mac addr in priv and rx channel and set it in EMAC hw */
memcpy(priv->mac_addr, sa->sa_data, ndev->addr_len);
- memcpy(rxch->mac_addr, sa->sa_data, ndev->addr_len);
memcpy(ndev->dev_addr, sa->sa_data, ndev->addr_len);
- emac_setmac(priv, EMAC_DEF_RX_CH, rxch->mac_addr);
+
+ /* If the interface is down - rxch is NULL. */
+ /* MAC address is configured only after the interface is enabled. */
+ if (netif_running(ndev)) {
+ memcpy(rxch->mac_addr, sa->sa_data, ndev->addr_len);
+ emac_setmac(priv, EMAC_DEF_RX_CH, rxch->mac_addr);
+ }
if (netif_msg_drv(priv))
dev_notice(emac_dev, "DaVinci EMAC: emac_dev_setmac_addr %s\n",
--
1.5.4.3
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