Re: BUG: enable_cpucache failed for radix_tree_node, error 12 (was: Re: [PATCH v3 9/9] slab: remove BAD_ALIEN_MAGIC)

From: Joonsoo Kim
Date: Thu Aug 07 2014 - 09:03:18 EST


2014-08-07 21:53 GMT+09:00 Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>:
> Hi,
>
> On Thu, Aug 7, 2014 at 2:36 PM, Joonsoo Kim <js1304@xxxxxxxxx> wrote:
>>> With latest mainline, I'm getting a crash during bootup on m68k/ARAnyM:
>>>
>>> enable_cpucache failed for radix_tree_node, error 12.
>>> kernel BUG at /scratch/geert/linux/linux-m68k/mm/slab.c:1522!
>
>>> I bisected it to commit a640616822b2c3a8009b0600f20c4a76ea8a0025
>>> Author: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
>>> Date: Wed Aug 6 16:04:38 2014 -0700
>>>
>>> slab: remove BAD_ALIEN_MAGIC
>
>> This patch only works for !NUMA. And if num_possible_nodes() is 1,
>> then it doesn't have any effect, because alloc_alien_cache() call is always
>> skipped. Is it possible !NUMA and num_possible_nodes() != 1?
>>
>> Could you check your config for CONFIG_NUMA and
>> CONFIG_NODES_SHIFT?
>
> $ grep CONFIG_NUMA .config
> $ grep CONFIG_NODES_SHIFT .config
> CONFIG_NODES_SHIFT=3
> $
>
> There are indeed multiple nodes:
>
> On node 0 totalpages: 3584
> free_area_init_node: node 0, pgdat 003659a4, node_mem_map 00402000
> DMA zone: 32 pages used for memmap
> DMA zone: 0 pages reserved
> DMA zone: 3584 pages, LIFO batch:0
> On node 1 totalpages: 65536
> free_area_init_node: node 1, pgdat 00366294, node_mem_map 00426090
> DMA zone: 576 pages used for memmap
> DMA zone: 0 pages reserved
> DMA zone: 65536 pages, LIFO batch:15
>
>> And, could you check booting with boot param "noaliencache"?
>
> That fixes the boot, too.

Ah... I don't know it can be possible to be !CONFIG_NUMA and
CONFIG_NODES_SHIFT > 0 until now. If so, I should revert this patch.

After some more investigation, I will revert this patch tomorrow and
notify you.

Thanks for reporting!!! :)
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