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From: Andrew Morton <akpm@linux-foundation.org>
To: aarcange@redhat.com, adelva@google.com,
	akpm@linux-foundation.org, andreyknvl@gmail.com,
	catalin.marinas@arm.com, Dave.Martin@arm.com, eugenis@google.com,
	linux-mm@kvack.org, lokeshgidra@google.com, mitchp@google.com,
	mm-commits@vger.kernel.org, pcc@google.com,
	stable@vger.kernel.org, torvalds@linux-foundation.org,
	vincenzo.frascino@arm.com, will@kernel.org,
	willmcvicker@google.com
Subject: [patch 02/15] selftest: use mmap instead of posix_memalign to allocate memory
Date: Fri, 23 Jul 2021 15:50:04 -0700	[thread overview]
Message-ID: <20210723225004.VMRataLna%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210723154926.c6cda0f262b1990b950a5886@linux-foundation.org>

From: Peter Collingbourne <pcc@google.com>
Subject: selftest: use mmap instead of posix_memalign to allocate memory

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 <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>
---

 tools/testing/selftests/vm/userfaultfd.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/tools/testing/selftests/vm/userfaultfd.c~selftest-use-mmap-instead-of-posix_memalign-to-allocate-memory
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -210,8 +210,10 @@ static void anon_release_pages(char *rel
 
 static void anon_allocate_area(void **alloc_area)
 {
-	if (posix_memalign(alloc_area, page_size, nr_pages * page_size))
-		err("posix_memalign() failed");
+	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
+			   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (*alloc_area == MAP_FAILED)
+		err("mmap of anonymous memory failed");
 }
 
 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
_

  parent reply	other threads:[~2021-07-23 22:50 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23 22:49 incoming Andrew Morton
2021-07-23 22:50 ` [patch 01/15] userfaultfd: do not untag user pointers Andrew Morton
2021-07-23 22:50 ` Andrew Morton [this message]
2021-07-23 22:50 ` [patch 03/15] kfence: defer kfence_test_init to ensure that kunit debugfs is created Andrew Morton
2021-07-23 22:50 ` [patch 04/15] kfence: move the size check to the beginning of __kfence_alloc() Andrew Morton
2021-07-23 22:50 ` [patch 05/15] kfence: skip all GFP_ZONEMASK allocations Andrew Morton
2021-07-23 22:50 ` [patch 06/15] mm: call flush_dcache_page() in memcpy_to_page() and memzero_page() Andrew Morton
2021-07-24  6:59   ` Christoph Hellwig
2021-07-24 16:23     ` Matthew Wilcox
2021-07-23 22:50 ` [patch 07/15] mm: use kmap_local_page in memzero_page Andrew Morton
2021-07-23 22:50 ` [patch 08/15] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction Andrew Morton
2021-07-23 22:50 ` [patch 09/15] memblock: make for_each_mem_range() traverse MEMBLOCK_HOTPLUG regions Andrew Morton
2021-07-23 22:50 ` [patch 10/15] writeback, cgroup: remove wb from offline list before releasing refcnt Andrew Morton
2021-07-23 22:50 ` [patch 11/15] writeback, cgroup: do not reparent dax inodes Andrew Morton
2021-07-23 22:50 ` [patch 12/15] mm/secretmem: wire up ->set_page_dirty Andrew Morton
2021-07-23 22:50 ` [patch 13/15] mm: mmap_lock: fix disabling preemption directly Andrew Morton
2021-07-23 22:50 ` [patch 14/15] mm: fix the deadlock in finish_fault() Andrew Morton
2021-07-23 22:50 ` [patch 15/15] hugetlbfs: fix mount mode command line processing Andrew Morton
2021-07-24  1:41   ` Al Viro
2021-07-26  5:22     ` Andrew Morton

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