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

[Srikar Dronamraju]

* Vlastimil Babka <vbabka at suse.cz> [2020-03-20 09:43:11]:

> On 3/20/20 8:46 AM, Srikar Dronamraju wrote:
> > * Vlastimil Babka <vbabka at suse.cz> [2020-03-19 15:10:19]:
> > 
> >> On 3/19/20 3:05 PM, Srikar Dronamraju wrote:
> >> > * Vlastimil Babka <vbabka at suse.cz> [2020-03-19 14:47:58]:
> >> > 
> >> 
> >> 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.
> >> 
> > 
> > Ah I probably got confused with your previous version where
> > alloc_slab_page() was modified. I see no problems with this version.
> 
> Thanks!
> 
> > Sorry for the noise.
> 
> No problem.
> 
> > A question just for my better understanding,
> > How worse would it be to set node to numa_mem_id() instead of NUMA_NODE_ID
> > when the current node is !N_NORMAL_MEMORY?
> 

Yes,

> (I'm assuming you mean s/NUMA_NODE_ID/NUMA_NO_NODE/)
> 
> Well, numa_mem_id() should work too, but it would make the allocation
> constrained to the node of current cpu, with all the consequences (deactivating
> percpu slab if it was from a different node etc).
> 
> There's no reason why this cpu's node should be the closest node to the one that
> was originally requested (but has no memory), so it's IMO pointless or even
> suboptimal to constraint to it. This can be revisited in case we get guaranteed
> existence of node data with zonelists for all possible nodes, but for now
> NUMA_NO_NODE seems the most reasonable fix to me.
> 

Okay.


-- 
Thanks and Regards
Srikar Dronamraju