Re: [PATCH 2/6] mm/mremap: For MREMAP_DONTUNMAP check security_vm_enough_memory_mm()

From: Brian Geffon
Date: Mon Dec 28 2020 - 13:25:01 EST


This looks good to me with a small comment.

> if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) {
> /* OOM: unable to split vma, just get accounts right */
> - if (vm_flags & VM_ACCOUNT)
> + if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP))
> vm_acct_memory(new_len >> PAGE_SHIFT);

Checking MREMAP_DONTUNMAP in the do_munmap path is unnecessary as
MREMAP_DONTUNMAP will have already returned by this point.