Re: ftdi_sio BUG: NULL pointer dereference

From: Mike Remski
Date: Wed Jun 04 2014 - 13:05:16 EST

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 =
Jun 4 11:35:20 nicA91A84 kernel: Oops: 0000 [#1] SMP
Jun 4 11:35:20 nicA91A84 kernel: last sysfs file:
Yeah, you really need to update your kernel. You'll definitely need at
least commit 99f347caa456 ("USB: CDC ACM: Fix NULL pointer

No more reports until you've tried a recent kernel, ok? ;)

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.

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