From 540eee8cbb3d281b0b3789a7ca7b862adce3373c Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Fri, 23 Jul 2021 15:50:04 -0700 Subject: [PATCH] selftest: use mmap instead of posix_memalign to allocate memory 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/Icac91064fcd923f77a83e8e133f8631c5b8fc241 Fixes: c47174fc362a ("userfaultfd: selftest") Co-developed-by: Lokesh Gidra Signed-off-by: Lokesh Gidra Signed-off-by: Peter Collingbourne Reviewed-by: Catalin Marinas Cc: Vincenzo Frascino Cc: Dave Martin Cc: Will Deacon Cc: Andrea Arcangeli Cc: Alistair Delva Cc: William McVicker Cc: Evgenii Stepanov Cc: Mitch Phillips Cc: Andrey Konovalov Cc: [5.4] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/vm/userfaultfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index d3362777a4258..17ac167823a6d 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -139,8 +139,10 @@ static int anon_release_pages(char *rel_area) 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; } } -- 2.47.3