msm_iommu_pagetable_prealloc_allocate, was: Re: [PATCH] mm/slab: improve kmem_cache_alloc_bulk
From: Christoph Hellwig
Date: Mon Jun 01 2026 - 03:57:44 EST
On Mon, Jun 01, 2026 at 03:39:06PM +0900, Harry Yoo wrote:
> > Ok, thanks. The two Sashiko complains also look like they had merrits,
> > but I won't get to looking into them until Monday.
> The review:
> https://sashiko.dev/#/patchset/20260528093437.2519248-2-hch%40lst.de
>
> So there is a user who might call kmem_cache_alloc_bulk() with size = 0
> (although the comment says @size must be larger than 0!) and
> kmem_cache_alloc_bulk() returning 0 was considered a success in that case.
>
> Either fixing kmem_cache_alloc_bulk() (and the comment) or fixing the
> user sounds fine to me.
>
> And yeah freeing an object via kfree() allocated via kvmalloc is a bug...
I think the right fix here is to check p->count somewhere in the msm
code and never get here. And the kfree/kvfree fix of course.
І.e. nothing to change in this patch, but a headsup for the MSM
maintainers.