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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