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

On Wed,  7 Jul 2021 11:43:13 -0700 Peter Collingbourne [off-list ref] 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.

Doesn't apply to current mainline.  Can you please resync and redo?

Co-developed-by: Lokesh Gidra <redacted>
Signed-off-by: Lokesh Gidra <redacted>
Signed-off-by: Peter Collingbourne <redacted>
Fixes: c47174fc362a ("userfaultfd: selftest")
Cc: <redacted> # 5.4

This patch then won't apply to earlier kenrels, so please be prepared
to help Greg resolve this.