From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpauth11.prod.mesa1.secureserver.net (smtpauth11.prod.mesa1.secureserver.net [64.202.165.33]) by ozlabs.org (Postfix) with SMTP id DBB97DDE42 for ; Sun, 10 Feb 2008 13:33:12 +1100 (EST) From: "Russell McGuire" To: Subject: HDLC driver - dev_free_skb_irq causes Segfault Date: Sat, 9 Feb 2008 18:32:16 -0800 Message-ID: <00be01c86b8d$27c2fcb0$6405a8c0@absolut> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00BF_01C86B4A.199FBCB0" Reply-To: rmcguire@videopresence.com List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. ------=_NextPart_000_00BF_01C86B4A.199FBCB0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit All, So I am in the process of debugging my newly established HDLC driver. More or less modeled after a simplified gianfar / ucc_geth idea. However, after loading, etc. and using the following commands -> insmod hdlc-8360.ko -> sethdlc hdlc0 hdlc-eth -> ifconfig hdlc0 up 192.168.1.100 All is well, and I am seeing IDL interrupts. Great. Now I go to ping an address like, ping 192.168.1.101 I can see that I get the start_xmit function, the IRQ from the QE comes back and reports the TXBD as successfully sent. Here is the problem, when I goto free the skb in the tx_handler, I get a 'Unable to Handle Kernel Paging Request for data at address 0x00000000' Even though for the life of me, I can't see any pointers that are at address zero. I have checked the pointer value I am passing in, and indeed it is the exact same pointer I am receiving from the original start-xmit call.. Are we supposed to copy the skb? And free it immediately in the start_xmit? Some special way to store the pointer? I have tried txbd->buf = skb->data; txbd->buf = virt_to_phys(skb->data); etc.. and various other ways to save that I have seen in the gianfar and ucc_geth drivers. My tx_sk_buff** is identical as alloced the same way. Anyone have any ideas? -Russ ------=_NextPart_000_00BF_01C86B4A.199FBCB0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable HDLC driver - dev_free_skb_irq causes Segfault

All,

So I am in the process of debugging my newly = established HDLC = driver.

More or less modeled after a simplified gianfar / = ucc_geth idea.

However, after loading, etc… and = using = the following = commands

-> insmod hdlc-8360.ko

-> sethdlc hdlc0 = hdlc-eth

-> = ifconfig hdlc0 up 192.168.1.100

All is = well, and I am seeing IDL = interrupts. Great.

Now I go = to ping an address like,

ping 192.168.1.101

I can = see that I get the start_xmit function, the IRQ from the QE comes back = and reports the TXBD as successfully sent.

Here = is the problem, when I goto free the skb in the tx_handler, = I get = a

‘Unable to Handle Kernel Paging = Request for data at address = 0x00000000’

Even though for the life of me, I = can’t see any pointers that are at address = zero.

I have = checked the pointer value I am passing in, and indeed it is the exact = same pointer I am receiving from the = original

start-xmit = call..

Are we = supposed = to copy the skb? And free it immediately in the start_xmit?

Some = special way to store the pointer?

I have = tried

txbd->buf =3D skb->data;

txbd->buf =3D virt_to_phys(skb->data);

etc.. and various other ways to save that I = have = seen in  the gianfar and = ucc_geth drivers.

My tx_sk_buff** is identical as alloced the same way…

Anyone have any ideas?

-Russ

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