Re: PTP + H/W time stamping + CONFIG_PREEMPT_RT_FULL == Oops in slab

On Thu, 2012-06-21 at 20:09 +0530, satpal parmar wrote:

Hi  All!

Recently  I successfully  integrated a certain
(http://sourceforge.net/scm/?type=svn&group_id=503885) open source
implementation of PTP protocol with Linux  3.0.1 running on ARM based
SoC. Since Phy  (Phyter DP 83640) on board  supported  H/W time
stamping support I am using for that for the same. Integration worked
smoothly  until I applied RT patch and enabled full preemption
(CONFIG_PREEMPT_RT_FULL).

[...]

kernel BUG at /home/satpal/sandbox/console_p/trunk/bts/source/vendor/linux/mm/slab.c:3205!
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = e9e08000
[00000000] *pgd=ae31c831, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1] PREEMPT
Modules linked in:
CPU: 0    Not tainted  (3.0.1-rt11-svn7595 #29)

[...]

I suggest you re-test with 3.0.35-rt56; there have been many bug fixes.

Also might this 'vendor' kernel include its own changes to mm, net, etc.
that are not in mainline?

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.