From: Peter Collingbourne pcc@google.com
commit 0db282ba2c12c1515d490d14a1ff696643ab0f1b upstream.
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.
Link: https://lkml.kernel.org/r/20210714195437.118982-3-pcc@google.com Link: https://linux-review.googlesource.com/id/Icac91064fcd923f77a83e8e133f8631c5b... Fixes: c47174fc362a ("userfaultfd: selftest") Co-developed-by: Lokesh Gidra lokeshgidra@google.com Signed-off-by: Lokesh Gidra lokeshgidra@google.com Signed-off-by: Peter Collingbourne pcc@google.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Cc: Vincenzo Frascino vincenzo.frascino@arm.com Cc: Dave Martin Dave.Martin@arm.com Cc: Will Deacon will@kernel.org Cc: Andrea Arcangeli aarcange@redhat.com Cc: Alistair Delva adelva@google.com Cc: William McVicker willmcvicker@google.com Cc: Evgenii Stepanov eugenis@google.com Cc: Mitch Phillips mitchp@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: stable@vger.kernel.org [5.4] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/vm/userfaultfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -129,8 +129,10 @@ static int anon_release_pages(char *rel_
static void anon_allocate_area(void **alloc_area) { - if (posix_memalign(alloc_area, page_size, nr_pages * page_size)) { - fprintf(stderr, "out of memory\n"); + *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (*alloc_area == MAP_FAILED) + fprintf(stderr, "mmap of anonymous memory failed"); *alloc_area = NULL; } }