Re: [PATCH -next v2] kunit: fix uninitialized variables bug in attributes filtering

[David Gow]

On Fri, 4 Aug 2023 at 03:37, Rae Moar <rmoar@xxxxxxxxxx> wrote:
>
> Fix smatch warnings regarding uninitialized variables in the filtering
> patch of the new KUnit Attributes feature.
>
> Fixes: 529534e8cba3 ("kunit: Add ability to filter attributes")
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/202307270610.s0w4NKEn-lkp@xxxxxxxxx/
>
> Signed-off-by: Rae Moar <rmoar@xxxxxxxxxx>
> ---
>
> Change since v1:
> - Changed initialization of filtered to be {NULL, NULL} at the start and
>   only updated when ready to return.
> - Remove unnecessary +1 in memory allocation for parsed_filters in
>   executor test.
>
> Note that this is rebased on top of the recent fix:
> ("kunit: fix possible memory leak in kunit_filter_suites()").

Thanks: this looks good to me now!

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

Cheers,
-- David

>
>  lib/kunit/attributes.c    | 40 +++++++++++++++++----------------------
>  lib/kunit/executor.c      | 18 +++++++++++-------
>  lib/kunit/executor_test.c |  2 +-
>  3 files changed, 29 insertions(+), 31 deletions(-)
>
> diff --git a/lib/kunit/attributes.c b/lib/kunit/attributes.c
> index d37c40c0ce4f..5e3034b6be99 100644
> --- a/lib/kunit/attributes.c
> +++ b/lib/kunit/attributes.c
> @@ -102,7 +102,7 @@ static int int_filter(long val, const char *op, int input, int *err)
>  static int attr_enum_filter(void *attr, const char *input, int *err,
>                 const char * const str_list[], int max)
>  {
> -       int i, j, input_int;
> +       int i, j, input_int = -1;
>         long test_val = (long)attr;
>         const char *input_val = NULL;
>
> @@ -124,7 +124,7 @@ static int attr_enum_filter(void *attr, const char *input, int *err,
>                         input_int = j;
>         }
>
> -       if (!input_int) {
> +       if (input_int < 0) {
>                 *err = -EINVAL;
>                 pr_err("kunit executor: invalid filter input: %s\n", input);
>                 return false;
> @@ -186,8 +186,10 @@ static void *attr_module_get(void *test_or_suite, bool is_test)
>         // Suites get their module attribute from their first test_case
>         if (test)
>                 return ((void *) test->module_name);
> -       else
> +       else if (kunit_suite_num_test_cases(suite) > 0)
>                 return ((void *) suite->test_cases[0].module_name);
> +       else
> +               return (void *) "";
>  }
>
>  /* List of all Test Attributes */
> @@ -221,7 +223,7 @@ const char *kunit_attr_filter_name(struct kunit_attr_filter filter)
>  void kunit_print_attr(void *test_or_suite, bool is_test, unsigned int test_level)
>  {
>         int i;
> -       bool to_free;
> +       bool to_free = false;
>         void *attr;
>         const char *attr_name, *attr_str;
>         struct kunit_suite *suite = is_test ? NULL : test_or_suite;
> @@ -255,7 +257,7 @@ void kunit_print_attr(void *test_or_suite, bool is_test, unsigned int test_level
>
>  int kunit_get_filter_count(char *input)
>  {
> -       int i, comma_index, count = 0;
> +       int i, comma_index = 0, count = 0;
>
>         for (i = 0; input[i]; i++) {
>                 if (input[i] == ',') {
> @@ -272,7 +274,7 @@ int kunit_get_filter_count(char *input)
>  struct kunit_attr_filter kunit_next_attr_filter(char **filters, int *err)
>  {
>         struct kunit_attr_filter filter = {};
> -       int i, j, comma_index, new_start_index;
> +       int i, j, comma_index = 0, new_start_index = 0;
>         int op_index = -1, attr_index = -1;
>         char op;
>         char *input = *filters;
> @@ -316,7 +318,7 @@ struct kunit_attr_filter kunit_next_attr_filter(char **filters, int *err)
>                 filter.attr = &kunit_attr_list[attr_index];
>         }
>
> -       if (comma_index) {
> +       if (comma_index > 0) {
>                 input[comma_index] = '\0';
>                 filter.input = input + op_index;
>                 input = input + new_start_index;
> @@ -356,31 +358,22 @@ struct kunit_suite *kunit_filter_attr_tests(const struct kunit_suite *const suit
>
>         /* Save filtering result on default value */
>         default_result = filter.attr->filter(filter.attr->attr_default, filter.input, err);
> -       if (*err) {
> -               kfree(copy);
> -               kfree(filtered);
> -               return NULL;
> -       }
> +       if (*err)
> +               goto err;
>
>         /* Save suite attribute value and filtering result on that value */
>         suite_val = filter.attr->get_attr((void *)suite, false);
>         suite_result = filter.attr->filter(suite_val, filter.input, err);
> -       if (*err) {
> -               kfree(copy);
> -               kfree(filtered);
> -               return NULL;
> -       }
> +       if (*err)
> +               goto err;
>
>         /* For each test case, save test case if passes filtering. */
>         kunit_suite_for_each_test_case(suite, test_case) {
>                 test_val = filter.attr->get_attr((void *) test_case, true);
>                 test_result = filter.attr->filter(filter.attr->get_attr(test_case, true),
>                                 filter.input, err);
> -               if (*err) {
> -                       kfree(copy);
> -                       kfree(filtered);
> -                       return NULL;
> -               }
> +               if (*err)
> +                       goto err;
>
>                 /*
>                  * If attribute value of test case is set, filter on that value.
> @@ -406,7 +399,8 @@ struct kunit_suite *kunit_filter_attr_tests(const struct kunit_suite *const suit
>                 }
>         }
>
> -       if (n == 0) {
> +err:
> +       if (n == 0 || *err) {
>                 kfree(copy);
>                 kfree(filtered);
>                 return NULL;
> diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> index 481901d245d0..dc295150c4e5 100644
> --- a/lib/kunit/executor.c
> +++ b/lib/kunit/executor.c
> @@ -127,19 +127,18 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
>  {
>         int i, j, k;
>         int filter_count = 0;
> -       struct kunit_suite **copy, *filtered_suite, *new_filtered_suite;
> -       struct suite_set filtered;
> +       struct kunit_suite **copy, **copy_start, *filtered_suite, *new_filtered_suite;
> +       struct suite_set filtered = {NULL, NULL};
>         struct kunit_glob_filter parsed_glob;
> -       struct kunit_attr_filter *parsed_filters;
> +       struct kunit_attr_filter *parsed_filters = NULL;
>
>         const size_t max = suite_set->end - suite_set->start;
>
>         copy = kmalloc_array(max, sizeof(*filtered.start), GFP_KERNEL);
> -       filtered.start = copy;
>         if (!copy) { /* won't be able to run anything, return an empty set */
> -               filtered.end = copy;
>                 return filtered;
>         }
> +       copy_start = copy;
>
>         if (filter_glob)
>                 kunit_parse_glob_filter(&parsed_glob, filter_glob);
> @@ -147,7 +146,11 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
>         /* Parse attribute filters */
>         if (filters) {
>                 filter_count = kunit_get_filter_count(filters);
> -               parsed_filters = kcalloc(filter_count + 1, sizeof(*parsed_filters), GFP_KERNEL);
> +               parsed_filters = kcalloc(filter_count, sizeof(*parsed_filters), GFP_KERNEL);
> +               if (!parsed_filters) {
> +                       kfree(copy);
> +                       return filtered;
> +               }
>                 for (j = 0; j < filter_count; j++)
>                         parsed_filters[j] = kunit_next_attr_filter(&filters, err);
>                 if (*err)
> @@ -166,7 +169,7 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
>                                 goto err;
>                         }
>                 }
> -               if (filter_count) {
> +               if (filter_count > 0 && parsed_filters != NULL) {
>                         for (k = 0; k < filter_count; k++) {
>                                 new_filtered_suite = kunit_filter_attr_tests(filtered_suite,
>                                                 parsed_filters[k], filter_action, err);
> @@ -195,6 +198,7 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
>
>                 *copy++ = filtered_suite;
>         }
> +       filtered.start = copy_start;
>         filtered.end = copy;
>
>  err:
> diff --git a/lib/kunit/executor_test.c b/lib/kunit/executor_test.c
> index 01280cb8d451..3e0a1c99cb4e 100644
> --- a/lib/kunit/executor_test.c
> +++ b/lib/kunit/executor_test.c
> @@ -119,7 +119,7 @@ static void parse_filter_attr_test(struct kunit *test)
>         filter_count = kunit_get_filter_count(filters);
>         KUNIT_EXPECT_EQ(test, filter_count, 2);
>
> -       parsed_filters = kunit_kcalloc(test, filter_count + 1, sizeof(*parsed_filters),
> +       parsed_filters = kunit_kcalloc(test, filter_count, sizeof(*parsed_filters),
>                         GFP_KERNEL);
>         for (j = 0; j < filter_count; j++) {
>                 parsed_filters[j] = kunit_next_attr_filter(&filters, &err);
>
> base-commit: 3bffe185ad11e408903d2782727877388d08d94e
> --
> 2.41.0.585.gd2178a4bd4-goog
>

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