+ selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch added to mm-unstable branch

+ selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: selftests/mm: allow uffd test to skip properly with no privilege
has been added to the -mm mm-unstable branch.  Its filename is
     selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: selftests/mm: allow uffd test to skip properly with no privilege
Date: Wed, 12 Apr 2023 12:45:20 -0400

Allow skip a unit test properly due to no privilege (e.g.  sigbus and
events tests).

Link: https://lkml.kernel.org/r/20230412164520.329163-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/uffd-common.c     |   27 ++++++++++-------
 tools/testing/selftests/mm/uffd-common.h     |    4 +-
 tools/testing/selftests/mm/uffd-stress.c     |    6 ++-
 tools/testing/selftests/mm/uffd-unit-tests.c |   10 +++---
 4 files changed, 29 insertions(+), 18 deletions(-)

--- a/tools/testing/selftests/mm/uffd-common.c~selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege
+++ a/tools/testing/selftests/mm/uffd-common.c
@@ -232,7 +232,7 @@ void uffd_stats_report(struct uffd_args
 	printf("\n");
 }
 
-void userfaultfd_open(uint64_t *features)
+int userfaultfd_open(uint64_t *features)
 {
 	struct uffdio_api uffdio_api;
 
@@ -241,18 +241,19 @@ void userfaultfd_open(uint64_t *features
 	else
 		uffd = uffd_open_sys(UFFD_FLAGS);
 	if (uffd < 0)
-		err("uffd open failed (dev=%d)", test_dev_userfaultfd);
+		return -1;
 	uffd_flags = fcntl(uffd, F_GETFD, NULL);
 
 	uffdio_api.api = UFFD_API;
 	uffdio_api.features = *features;
 	if (ioctl(uffd, UFFDIO_API, &uffdio_api))
-		err("UFFDIO_API failed.\nPlease make sure to "
-		    "run with either root or ptrace capability.");
+		/* Probably lack of CAP_PTRACE? */
+		return -1;
 	if (uffdio_api.api != UFFD_API)
 		err("UFFDIO_API error: %" PRIu64, (uint64_t)uffdio_api.api);
 
 	*features = uffdio_api.features;
+	return 0;
 }
 
 static inline void munmap_area(void **area)
@@ -295,7 +296,7 @@ static void uffd_test_ctx_clear(void)
 	munmap_area((void **)&area_remap);
 }
 
-int uffd_test_ctx_init(uint64_t features)
+int uffd_test_ctx_init(uint64_t features, const char **errmsg)
 {
 	unsigned long nr, cpu;
 	int ret;
@@ -303,13 +304,19 @@ int uffd_test_ctx_init(uint64_t features
 	uffd_test_ctx_clear();
 
 	ret = uffd_test_ops->allocate_area((void **)&area_src, true);
-	if (ret)
-		return ret;
-	ret = uffd_test_ops->allocate_area((void **)&area_dst, false);
-	if (ret)
+	ret |= uffd_test_ops->allocate_area((void **)&area_dst, false);
+	if (ret) {
+		if (errmsg)
+			*errmsg = "memory allocation failed";
 		return ret;
+	}
 
-	userfaultfd_open(&features);
+	ret = userfaultfd_open(&features);
+	if (ret) {
+		if (errmsg)
+			*errmsg = "possible lack of priviledge";
+		return ret;
+	}
 
 	count_verify = malloc(nr_pages * sizeof(unsigned long long));
 	if (!count_verify)
--- a/tools/testing/selftests/mm/uffd-common.h~selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege
+++ a/tools/testing/selftests/mm/uffd-common.h
@@ -101,8 +101,8 @@ extern uffd_test_ops_t hugetlb_uffd_test
 extern uffd_test_ops_t *uffd_test_ops;
 
 void uffd_stats_report(struct uffd_args *args, int n_cpus);
-int uffd_test_ctx_init(uint64_t features);
-void userfaultfd_open(uint64_t *features);
+int uffd_test_ctx_init(uint64_t features, const char **errmsg);
+int userfaultfd_open(uint64_t *features);
 int uffd_read_msg(int ufd, struct uffd_msg *msg);
 void wp_range(int ufd, __u64 start, __u64 len, bool wp);
 void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args);
--- a/tools/testing/selftests/mm/uffd-stress.c~selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege
+++ a/tools/testing/selftests/mm/uffd-stress.c
@@ -271,7 +271,8 @@ static int userfaultfd_stress(void)
 	struct uffd_args args[nr_cpus];
 	uint64_t mem_size = nr_pages * page_size;
 
-	uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);
+	if (uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED, NULL))
+		err("context init failed");
 
 	if (posix_memalign(&area, page_size, page_size))
 		err("out of memory");
@@ -435,7 +436,8 @@ static void parse_test_type_arg(const ch
 	 * feature.
 	 */
 
-	userfaultfd_open(&features);
+	if (userfaultfd_open(&features))
+		err("Userfaultfd open failed");
 
 	test_uffdio_wp = test_uffdio_wp &&
 		(features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
--- a/tools/testing/selftests/mm/uffd-unit-tests.c~selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege
+++ a/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -172,7 +172,8 @@ out:
  * This function initializes the global variables.  TODO: remove global
  * vars and then remove this.
  */
-static int uffd_setup_environment(uffd_test_case_t *test, mem_type_t *mem_type)
+static int uffd_setup_environment(uffd_test_case_t *test, mem_type_t *mem_type,
+				  const char **errmsg)
 {
 	map_shared = mem_type->shared;
 	uffd_test_ops = mem_type->mem_ops;
@@ -186,7 +187,7 @@ static int uffd_setup_environment(uffd_t
 	/* TODO: remove this global var.. it's so ugly */
 	nr_cpus = 1;
 
-	return uffd_test_ctx_init(test->uffd_feature_required);
+	return uffd_test_ctx_init(test->uffd_feature_required, errmsg);
 }
 
 static bool uffd_feature_supported(uffd_test_case_t *test)
@@ -835,6 +836,7 @@ int main(int argc, char *argv[])
 	uffd_test_case_t *test;
 	mem_type_t *mem_type;
 	char test_name[128];
+	const char *errmsg;
 	int has_uffd;
 	int i, j;
 
@@ -860,8 +862,8 @@ int main(int argc, char *argv[])
 				uffd_test_skip("feature missing");
 				continue;
 			}
-			if (uffd_setup_environment(test, mem_type)) {
-				uffd_test_skip("environment setup failed");
+			if (uffd_setup_environment(test, mem_type, &errmsg)) {
+				uffd_test_skip(errmsg);
 				continue;
 			}
 			test->uffd_fn();
_

Patches currently in -mm which might be from peterx@redhat.com are

mm-khugepaged-check-again-on-anon-uffd-wp-during-isolation.patch
revert-userfaultfd-dont-fail-on-unrecognized-features.patch
selftests-mm-update-gitignore-with-two-missing-tests.patch
selftests-mm-dump-a-summary-in-run_vmtestssh.patch
selftests-mm-merge-utilh-into-vm_utilh.patch
selftests-mm-use-test_gen_progs-where-proper.patch
selftests-mm-link-vm_utilc-always.patch
selftests-mm-merge-default_huge_page_size-into-one.patch
selftests-mm-use-pm_-macros-in-vm_utilsh.patch
selftests-mm-reuse-pagemap_get_entry-in-vm_utilh.patch
selftests-mm-test-uffdio_zeropage-only-when-hugetlb.patch
selftests-mm-drop-test_uffdio_zeropage_eexist.patch
selftests-mm-create-uffd-common.patch
selftests-mm-split-uffd-tests-into-uffd-stress-and-uffd-unit-tests.patch
selftests-mm-uffd_register.patch
selftests-mm-uffd_open_devsys.patch
selftests-mm-uffdio_api-test.patch
selftests-mm-drop-global-mem_fd-in-uffd-tests.patch
selftests-mm-drop-global-hpage_size-in-uffd-tests.patch
selftests-mm-rename-uffd_stats-to-uffd_args.patch
selftests-mm-let-uffd_handle_page_fault-take-wp-parameter.patch
selftests-mm-allow-allocate_area-to-fail-properly.patch
selftests-mm-add-framework-for-uffd-unit-test.patch
selftests-mm-move-uffd-pagemap-test-to-unit-test.patch
selftests-mm-move-uffd-minor-test-to-unit-test.patch
selftests-mm-move-uffd-sig-events-tests-into-uffd-unit-tests.patch
selftests-mm-move-zeropage-test-into-uffd-unit-tests.patch
selftests-mm-workaround-no-way-to-detect-uffd-minor-wp.patch
selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch
selftests-mm-drop-sys-dev-test-in-uffd-stress-test.patch
selftests-mm-add-shmem-private-test-to-uffd-stress.patch
selftests-mm-add-uffdio-register-ioctls-test.patch