[5.6.0-rc2-next-20200218/powerpc] Boot failure on POWER9

[Vlastimil Babka]

On 2/27/20 5:00 PM, Sachin Sant wrote:
> 
> 
>> On 27-Feb-2020, at 5:42 PM, Michal Hocko <mhocko at kernel.org> wrote:
>> 
>> A very good hint indeed. I would do this
>> diff --git a/include/linux/topology.h b/include/linux/topology.h
>> index eb2fe6edd73c..d9f1b6737e4d 100644
>> --- a/include/linux/topology.h
>> +++ b/include/linux/topology.h
>> @@ -137,6 +137,8 @@ static inline void set_numa_mem(int node)
>> {
>> 	this_cpu_write(_numa_mem_, node);
>> 	_node_numa_mem_[numa_node_id()] = node;
>> +	pr_info("%s %d -> %d\n", __FUNCTION__, numa_node_id(), node);
>> +	dump_stack();
>> }
>> #endif
>> 
>> Btw. it would be also helpful to get
>> `faddr2line ___slab_alloc+0x334' from your kernel Sachin.
> 
> [linux-next]# ./scripts/faddr2line ./vmlinux ___slab_alloc+0x334 
> ___slab_alloc+0x334/0x760:
> new_slab_objects at mm/slub.c:2478
> (inlined by) ___slab_alloc at mm/slub.c:2628
> [linux-next]# 

Hmm that doesn't look relevant, but that address was marked as unreliable, no?
Don't we actually need this one?

[    8.768727] NIP [c0000000003d55f4] ___slab_alloc+0x1f4/0x760

> I have also attached boot log with a kernel that include about change.
> I see the following o/p during boot:
> 
> [    0.005269] set_numa_mem 1 -> 1

So there's no "set_numa_mem 0 -> X", specifically not
"set_numa_mem 0 -> 1" which I would have expected. That seems to confirm my
suspicion that the arch code doesn't set up the memoryless node 0 properly.

> [    0.005270] CPU: 12 PID: 0 Comm: swapper/12 Not tainted 5.6.0-rc3-next-20200227-autotest+ #6
> [    0.005271] Call Trace:
> [    0.005272] [c0000008b37dfe80] [c000000000b5d948] dump_stack+0xbc/0x104 (unreliable)
> [    0.005274] [c0000008b37dfec0] [c000000000059320] start_secondary+0x600/0x6e0
> [    0.005277] [c0000008b37dff90] [c00000000000ac54] start_secondary_prolog+0x10/0x14
> 
> Thanks
> -Sachin
>