[PATCH v4 2/2] selftest: use mmap instead of posix_memalign to allocate memory

[Catalin Marinas]

On Wed, Jul 07, 2021 at 11:43:13AM -0700, Peter Collingbourne wrote:
> This test passes pointers obtained from anon_allocate_area to the
> userfaultfd and mremap APIs. This causes a problem if the system
> allocator returns tagged pointers because with the tagged address ABI
> the kernel rejects tagged addresses passed to these APIs, which would
> end up causing the test to fail. To make this test compatible with
> such system allocators, stop using the system allocator to allocate
> memory in anon_allocate_area, and instead just use mmap.
> 
> Co-developed-by: Lokesh Gidra <lokeshgidra at google.com>
> Signed-off-by: Lokesh Gidra <lokeshgidra at google.com>
> Signed-off-by: Peter Collingbourne <pcc at google.com>
> Fixes: c47174fc362a ("userfaultfd: selftest")
> Cc: <stable at vger.kernel.org> # 5.4
> Link: https://linux-review.googlesource.com/id/Icac91064fcd923f77a83e8e133f8631c5b8fc241

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>