Oops in mpc52xx_uart_init (2.6.34-rc5)

Oops in mpc52xx_uart_init (2.6.34-rc5)

[Leonardo Chiquitto]

[-- Attachment #1: Type: text/plain, Size: 565 bytes --]

Hello,

Kernel 2.6.34-rc5 crashes on boot in a ppc32 machine (Mac Mini G4).

Reverting the following commit makes the kernel boot normally again:

commit 6acc6833510db8f72b5ef343296d97480555fda9
Author: Anatolij Gustschin <agust@denx.de>
Date:   Tue Feb 16 22:30:03 2010 -0700

    serial: mpc52xx_uart: re-enable mpc5121 PSC UART support

I'm attaching a photo with the panic message and call trace (I apologize
for the poor image quality and cropped left border). Please let me know if I
can provide any other info to help debugging this issue.

Thanks,
Leonardo

[-- Attachment #2: mpc52xx-oops.jpg --]
[-- Type: image/jpeg, Size: 101883 bytes --]

Re: Oops in mpc52xx_uart_init (2.6.34-rc5)

[Anatolij Gustschin]

On Tue, 4 May 2010 17:39:25 -0300
Leonardo Chiquitto <leonardo.lists@gmail.com> wrote:

> Kernel 2.6.34-rc5 crashes on boot in a ppc32 machine (Mac Mini G4).
> 
> Reverting the following commit makes the kernel boot normally again:
> 
> commit 6acc6833510db8f72b5ef343296d97480555fda9
> Author: Anatolij Gustschin <agust@denx.de>
> Date:   Tue Feb 16 22:30:03 2010 -0700
> 
>     serial: mpc52xx_uart: re-enable mpc5121 PSC UART support
> 
> I'm attaching a photo with the panic message and call trace (I apologize
> for the poor image quality and cropped left border). Please let me know if I
> can provide any other info to help debugging this issue.

Thanks for the bug report! This info is enough, I will submit a
fix soon.

Thanks,
Anatolij

[PATCH] serial: mpc52xx_uart: fix null pointer dereference

[Anatolij Gustschin]

Commit 6acc6833510db8f72b5ef343296d97480555fda9
introduced NULL pointer dereference and kernel crash
on ppc32 machines while booting. Fix this bug now.

Reported-by: Leonardo Chiquitto <leonardo.lists@gmail.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
---
 drivers/serial/mpc52xx_uart.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index a176ab4..02469c3 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -1467,7 +1467,7 @@ mpc52xx_uart_init(void)
 	/*
 	 * Map the PSC FIFO Controller and init if on MPC512x.
 	 */
-	if (psc_ops->fifoc_init) {
+	if (psc_ops && psc_ops->fifoc_init) {
 		ret = psc_ops->fifoc_init();
 		if (ret)
 			return ret;
-- 
1.7.0.4

Re: [PATCH] serial: mpc52xx_uart: fix null pointer dereference

[Leonardo Chiquitto]

On Tue, May 4, 2010 at 7:18 PM, Anatolij Gustschin <agust@denx.de> wrote:
> Commit 6acc6833510db8f72b5ef343296d97480555fda9
> introduced NULL pointer dereference and kernel crash
> on ppc32 machines while booting. Fix this bug now.
>
> Reported-by: Leonardo Chiquitto <leonardo.lists@gmail.com>
> Signed-off-by: Anatolij Gustschin <agust@denx.de>
> ---
> =A0drivers/serial/mpc52xx_uart.c | =A0 =A02 +-
> =A01 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.=
c
> index a176ab4..02469c3 100644
> --- a/drivers/serial/mpc52xx_uart.c
> +++ b/drivers/serial/mpc52xx_uart.c
> @@ -1467,7 +1467,7 @@ mpc52xx_uart_init(void)
> =A0 =A0 =A0 =A0/*
> =A0 =A0 =A0 =A0 * Map the PSC FIFO Controller and init if on MPC512x.
> =A0 =A0 =A0 =A0 */
> - =A0 =A0 =A0 if (psc_ops->fifoc_init) {
> + =A0 =A0 =A0 if (psc_ops && psc_ops->fifoc_init) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0ret =3D psc_ops->fifoc_init();
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (ret)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0return ret;
> --
> 1.7.0.4

Thanks for the quick fix, Anatolij. I just tested it and confirm it resolve=
s
the problem.

Leonardo

Re: [PATCH] serial: mpc52xx_uart: fix null pointer dereference

[Grant Likely]

On Wed, May 5, 2010 at 12:18 AM, Anatolij Gustschin <agust@denx.de> wrote:
> Commit 6acc6833510db8f72b5ef343296d97480555fda9
> introduced NULL pointer dereference and kernel crash
> on ppc32 machines while booting. Fix this bug now.
>
> Reported-by: Leonardo Chiquitto <leonardo.lists@gmail.com>
> Signed-off-by: Anatolij Gustschin <agust@denx.de>

Thanks for being so quick to pick up on this Anatolij.  I've been
traveling and not able to respond to stuff.  I see that Greg has
already picked this up (thanks Greg!), but FWIW:

Acked-by: Grant Likely <grant.likely@secretlab.ca>

Actually, now that I look, this fix needs to go into Linus' tree right
away (not just linux-next) since the offending patch went in during
the 2.6.34 merge window.

Greg, I can either pick this up and push it out to Linus tomorrow, or
let you do it.  Whichever you prefer.  Let me know so I don't cause
conflicts in your tree.

On another note, this patch isn't actually the right fix, but that's
because this driver is such a horribly bad example of handling private
data that doing the right thing requires some re-architecting.  The
driver should not need any of that extra code in the module_init hook.
 For now this is the best thing to do, but I'll dig into it tomorrow
and see if I can churn out a patch to fix it properly for the 2.6.35
merge window.

Cheers and thanks,
g.

> ---
> =A0drivers/serial/mpc52xx_uart.c | =A0 =A02 +-
> =A01 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.=
c
> index a176ab4..02469c3 100644
> --- a/drivers/serial/mpc52xx_uart.c
> +++ b/drivers/serial/mpc52xx_uart.c
> @@ -1467,7 +1467,7 @@ mpc52xx_uart_init(void)
> =A0 =A0 =A0 =A0/*
> =A0 =A0 =A0 =A0 * Map the PSC FIFO Controller and init if on MPC512x.
> =A0 =A0 =A0 =A0 */
> - =A0 =A0 =A0 if (psc_ops->fifoc_init) {
> + =A0 =A0 =A0 if (psc_ops && psc_ops->fifoc_init) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0ret =3D psc_ops->fifoc_init();
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (ret)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0return ret;
> --
> 1.7.0.4
>
>



--=20
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

Re: [PATCH] serial: mpc52xx_uart: fix null pointer dereference

[Greg KH]

On Mon, May 10, 2010 at 12:04:30AM +0200, Grant Likely wrote:
> On Wed, May 5, 2010 at 12:18 AM, Anatolij Gustschin <agust@denx.de> wrote:
> > Commit 6acc6833510db8f72b5ef343296d97480555fda9
> > introduced NULL pointer dereference and kernel crash
> > on ppc32 machines while booting. Fix this bug now.
> >
> > Reported-by: Leonardo Chiquitto <leonardo.lists@gmail.com>
> > Signed-off-by: Anatolij Gustschin <agust@denx.de>
> 
> Thanks for being so quick to pick up on this Anatolij.  I've been
> traveling and not able to respond to stuff.  I see that Greg has
> already picked this up (thanks Greg!), but FWIW:
> 
> Acked-by: Grant Likely <grant.likely@secretlab.ca>
> 
> Actually, now that I look, this fix needs to go into Linus' tree right
> away (not just linux-next) since the offending patch went in during
> the 2.6.34 merge window.
> 
> Greg, I can either pick this up and push it out to Linus tomorrow, or
> let you do it.  Whichever you prefer.  Let me know so I don't cause
> conflicts in your tree.

I have 2 other tty/serial fixes to go to Linus for .34 along with this
one, so I'll be glad to send it to him.  I've added your ack to the
patch.

thanks,

greg k-h

Re: [PATCH] serial: mpc52xx_uart: fix null pointer dereference

[Grant Likely]

On Mon, May 10, 2010 at 6:25 PM, Greg KH <gregkh@suse.de> wrote:
> On Mon, May 10, 2010 at 12:04:30AM +0200, Grant Likely wrote:
>> Greg, I can either pick this up and push it out to Linus tomorrow, or
>> let you do it. =A0Whichever you prefer. =A0Let me know so I don't cause
>> conflicts in your tree.
>
> I have 2 other tty/serial fixes to go to Linus for .34 along with this
> one, so I'll be glad to send it to him. =A0I've added your ack to the
> patch.

Perfect.  Thanks Greg.

g.