On Fri, May 24, 2024 at 11:01:40AM -0400, Kent Overstreet wrote: > On Wed, Apr 24, 2024 at 02:40:59PM -0700, Kees Cook wrote: > > To be able to choose which buckets to allocate from, make the buckets > > available to the lower level kmalloc interfaces by adding them as the > > first argument. Where the bucket is not available, pass NULL, which means > > "use the default system kmalloc bucket set" (the prior existing behavior), > > as implemented in kmalloc_slab(). > > I thought the plan was to use codetags for this? That would obviate the > need for all this plumbing. > > Add fields to the alloc tag for: > - allocation size (or 0 if it's not a compile time constant) > - union of kmem_cache, kmem_buckets, depending on whether the > allocation size is constant or not I want to provide "simple" (low-hanging fruit) coverage that can live separately from the codetags-based coverage. The memory overhead for this patch series is negligible, but I suspect the codetags expansion, while not giant, will be more than some deployments will want. I want to avoid an all-or-nothing solution -- which is why I had intended this to be available "by default". But I will respin this with kmem_buckets under a Kconfig. -- Kees Cook
