On Thu, Nov 3, 2016 at 1:33 PM, Christoph Lameter <cl@xxxxxxxxx> wrote: > On Wed, 2 Nov 2016, David Rientjes wrote: > >> > Christoph on the first version advised removing invalid flags on the >> > caller and checking they are correct in kmem_cache_create. The memcg >> > path putting the wrong flags is through create_cache but I still used >> > this approach. >> > >> >> I think this is a rather trivial point since it doesn't matter if we clear >> invalid flags on the caller or in the callee and obviously >> kmem_cache_create() does it in the callee. > > In order to be correct we need to do the following: > > kmem_cache_create should check for invalid flags (and that includes > internal alloocator flgs) being set and refuse to create the slab cache. > > memcg needs to call kmem_cache_create without any internal flags. > I am not sure that is possible. kmem_cache_create currently check for possible alias, I assume that it goes against what memcg tries to do. Separate the changes in two patches might make sense: 1) Fix the original bug by masking the flags passed to create_cache 2) Add flags check in kmem_cache_create. Does it make sense? > I also want to make sure that there are no other callers that specify > extraneou flags while we are at it. > I will review as many as I can but we might run into surprises (quick boot on defconfig didn't show anything). That's why having two different patches might be useful. -- Thomas -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>