Re: ftdi_sio BUG: NULL pointer dereference

[Johan Hovold <jhovold@gmail.com>]

On Wed, Jun 04, 2014 at 01:05:03PM -0400, Mike Remski wrote:
> On 06/04/2014 12:00 PM, Johan Hovold wrote:
> > On Wed, Jun 04, 2014 at 11:41:47AM -0400, Mike Remski wrote:
> >> Ok, had a chance to try the cdc-acm;  yes it's the ancient one that is
> >> in the base install of CentOS 6.4 (2.6.32-71.29.1 centos patched).  I'm
> >> hitting something similar;  I noticed there where a few commits for NULL
> >> pointer dereferences in cdc-acm.c.
> >>
> >> I'll poke into this a bit (yes, I know try a newer kernel, etc) and let
> >> you know what I find (or perhaps this looks similar to something already
> >> seen?).  This device is the same as the original ftdi crash, 1.2 is the
> >> same interface with bNumEndpoints == 0.
> >>
> >> Jun  4 11:35:20 nicA91A84 kernel: cdc_acm 5-2:1.2: This device cannot do
> >> calls on its own. It is not a modem.
> >> Jun  4 11:35:20 nicA91A84 kernel: BUG: unable to handle kernel NULL
> >> pointer dereference at 00000004
> >> Jun  4 11:35:20 nicA91A84 kernel: IP: [<f84f9c9e>]
> >> acm_probe+0x44e/0x127c [cdc_acm]
> >> Jun  4 11:35:20 nicA91A84 kernel: *pdpt = 00000000354eb001 *pde =
> >> 000000007f003067
> >> Jun  4 11:35:20 nicA91A84 kernel: Oops: 0000 [#1] SMP
> >> Jun  4 11:35:20 nicA91A84 kernel: last sysfs file:
> >> /sys/devices/pci0000:00/0000:00:1d.0/usb5/5-2/product
> > Yeah, you really need to update your kernel. You'll definitely need at
> > least commit 99f347caa456 ("USB: CDC ACM: Fix NULL pointer
> > dereference").
> >
> > No more reports until you've tried a recent kernel, ok? ;)
> >
> > Johan
> Device in question does not cause kernel crash when using the cdc-acm 
> driver on  a Fedora 19 system running Fedora kernel 3.9.5-301.
> 
> Thanks for all the help, I'll take care of my ancient kernels.

That's good to hear. Good luck with the backporting.

Johan