Re: [PATCH v1 16/16] mm/memory: support VM_MIXEDMAP in zap_special_vma_range()

Jason Gunthorpe
2026-03-11T12:04:27Z

On Wed, Mar 11, 2026 at 09:38:45AM +0000, Alice Ryhl wrote:
> It doesn't really make sense to have multiple binder VMAs. What happens
> with Rust Binder is that process A is receiving transactions and has the
> VMA mapped once.

IIRC the problem is the kernel doesn't guarentee singleton VMAs,
userspace can always clone them with fork or something. Did binder
solve this somehow?

Since you can't assume there is only one VMA the locking becomes a
mess to cover all the cases where userspace can trigger a VMA clone.

address space deals with this internally.

Thus, zap_special_vma_range() is extremely hard to use.

Jason