Hello, Michael:
Please look at v03 of the patch set which was posted
just on 09/25/2018. We had a last minute brainstorm of how
to simplify the code after the v02 REPOST.
Also, note that we would like to invalidate the set,
[PATCH v08 0/5] powerpc/hotplug: Update affinity for migrated CPUs
https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-July/176301.html
as we think it is covered now by other code.
Thanks for your attention and assistance.
Michael
On 09/26/2018 07:13 AM, Michael Ellerman wrote:
> On Thu, 2018-09-20 at 16:45:13 UTC, Michael Bringmann wrote:
>> After migration of a powerpc LPAR, the kernel executes code to
>> update the system state to reflect new platform characteristics.
>> Such changes include modifications to device tree properties
>> provided to the system by PHYP. Property notifications received
>> by the powerpc 'migration_store' code are passed along to the
>> kernel in general through a call to 'of_update_property' which
>> in turn passes such events back to all modules through entries like
>> the '.notifier_call' function within the NUMA module. When the
>> NUMA module updates its state, it resets its event timer. If this
>> occurs after a previous call to 'stop_topology_update' or on a
>> system without VPHN enabled, the code runs into an unitialized
>> timer structure and crashes. This patch adds a safety check
>> along this path toward the problem code.
>>
>> Note: This crash was observed on every LPM in the 4.17-rc7 kernel
>> (and in the 4.18 kernel) of a system with dedicated CPUs enabled.
>> An example crash log without the patch is as follows.
>>
> ...
>>
>> Signed-off-by: Michael Bringmann <m...@linux.vnet.ibm.com>
>
> Applied to powerpc fixes, thanks.
>
> https://git.kernel.org/powerpc/c/8604895a34d92f5e186ceb931b0d1b
>
> cheers
>
>
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
m...@linux.vnet.ibm.com
