selftests/mm: allow uffd test to skip properly with no privilege

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

[colin.i.king@gmail.com: fix spelling mistake "priviledge" -> "privilege"]
Link: https://lkml.kernel.org/r/20230414081506.1678998-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/20230412164520.329163-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.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>

diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
index 12ac84712a380b84479f075b60ec16da17e8f4fd..3e98e129f8bd0f38ced18f56848891cdfbb238ba 100644 (file)
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -232,7 +232,7 @@ void uffd_stats_report(struct uffd_args *args, int n_cpus)
        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)

diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
index 4bd5915cf5b43f136171b4fb750c1396e292e5ce..32e590ce94423411393608041a929f984f9b73f8 100644 (file)
--- a/tools/testing/selftests/mm/uffd-common.h
+++ b/tools/testing/selftests/mm/uffd-common.h
@@ -101,8 +101,8 @@ extern uffd_test_ops_t hugetlb_uffd_test_ops;
 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);

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index d78f888500111342f2a6e00e3f00780eddb3ed4e..c0e804f0500248348751bc12604987628d16180d 100644 (file)
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/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 char *raw_type)
         * feature.
         */
 
-       userfaultfd_open(&features);
+       if (userfaultfd_open(&features))
+               err("Userfaultfd open failed");
 
        test_uffdio_wp = test_uffdio_wp &&
                (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index a33d6c928eeb3daac1b275fcdc1ce3842bd175dc..b0acf558e8cb3c7950f2fcb347ec9566e62f5667 100644 (file)
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/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_test_case_t *test, mem_type_t *mem_type)
        /* 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();