[RFC 1/2] mm, slub: prevent kmalloc_node crashes and memory leaks

[Vlastimil Babka]

On 3/19/20 3:05 PM, Srikar Dronamraju wrote:
> * Vlastimil Babka <vbabka at suse.cz> [2020-03-19 14:47:58]:
> 
>> ----8<----
>> diff --git a/mm/slub.c b/mm/slub.c
>> index 17dc00e33115..7113b1f9cd77 100644
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -1973,8 +1973,6 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
>> 
>>  	if (node == NUMA_NO_NODE)
>>  		searchnode = numa_mem_id();
>> -	else if (!node_present_pages(node))
>> -		searchnode = node_to_mem_node(node);
>> 
>>  	object = get_partial_node(s, get_node(s, searchnode), c, flags);
> 
> Are we okay with passing a node to get_partial_node with !NUMA_NO_NODE and
> !N_MEMORY including possible nodes?

No, but AFAICS, such node values are already handled in ___slab_alloc, and
cannot reach get_partial(). If you see something I missed, please do tell.

>>  	if (object || node != NUMA_NO_NODE)
>