From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: A small fix to davinci_emac driver Date: Thu, 25 Jun 2009 06:34:38 -0700 Message-ID: <87ocscsahd.fsf@deeprootsystems.com> References: <028901c9f54b$4579eae0$d06dc0a0$@com> <7448ec710906250613p5fde8b44s24842a32e42dce37@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Nori\, Sekhar" , netdev@vger.kernel.org, davinci-linux-open-source@linux.davincidsp.com To: Pablo Bitton Return-path: Received: from mail-px0-f190.google.com ([209.85.216.190]:63543 "EHLO mail-px0-f190.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753969AbZFYNei (ORCPT ); Thu, 25 Jun 2009 09:34:38 -0400 Received: by pxi28 with SMTP id 28so1035043pxi.33 for ; Thu, 25 Jun 2009 06:34:41 -0700 (PDT) In-Reply-To: <7448ec710906250613p5fde8b44s24842a32e42dce37@mail.gmail.com> (Pablo Bitton's message of "Thu\, 25 Jun 2009 16\:13\:59 +0300") Sender: netdev-owner@vger.kernel.org List-ID: Pablo Bitton writes: > 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. This should go linux-net after a signoff from Sekhar or Chaithrika. > 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). You can send via Gmail using git-send-email directly. Read this: http://git.or.cz/gitwiki/GitTips#Mail Kevin > Remarks are welcomed. > > Thanks in advance. > > On Thu, Jun 25, 2009 at 11:31 AM, Nori, Sekhar 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.bitton@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 > 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 > --- > 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 > > _______________________________________________ > Davinci-linux-open-source mailing list > Davinci-linux-open-source@linux.davincidsp.com > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source