Re: [PATCH v4 6/6] kselftest: alloc_tag: extend the allocinfo ioctl kselftest

[Hao Ge <hao.ge@linux.dev>]

Hi Abhishek


On 2026/6/10 08:12, Abhishek Bapat wrote:
> Add the following 2 scenarios to the allocinfo ioctl kselftest:
> 1. Validate size based filtering
> 2. Validate lineno based filtering
>
> The first test uses "do_init_module" as the candidate function for the
> test. This is because the associated site will only allocate memory when
> a kernel module is loaded. The return value of get_content_id() changes
> every time modules are loaded or unloaded. Hence, as long as
> get_content_id() values at the start and the end of the test are the
> same, the memory allocated by the do_init_module call site should also
> remain the same. Consequently, the test can assume consistency between
> the value returned by the ioctl and the procfs resulting in less
> flakiness.
>
> Signed-off-by: Abhishek Bapat <abhishekbapat@google.com>
> ---
>   .../alloc_tag/allocinfo_ioctl_test.c          | 204 +++++++++++++++++-
>   1 file changed, 203 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c b/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
> index cd9cf229ae1f..5d2f13900a47 100644
> --- a/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
> +++ b/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
> @@ -311,11 +311,201 @@ static int test_function_filter(void)
>   	return run_filter_test(&filter);
>   }
>   
> +static int test_size_filter(void)
> +{
> +	int fd;
> +	struct allocinfo_tag_data_vec *tags = malloc(sizeof(*tags));
> +	struct allocinfo_tag_data_vec *procfs_entries = malloc(sizeof(*procfs_entries));
> +	struct allocinfo_filter filter;
> +	int ret = KSFT_PASS;
> +	__u64 target_size, i, pos;
> +	bool found;
> +	const char *target_function = "do_init_module";
> +	struct allocinfo_content_id start_cont_id, end_cont_id;
> +	int retry = 0;
> +	const int max_retries = 10;
> +
> +	if (!tags || !procfs_entries) {
> +		ksft_print_msg("Memory allocation failed.\n");
> +		ret = KSFT_FAIL;
> +		goto freemem;
> +	}
> +
> +	fd = open(ALLOCINFO_PROC, O_RDONLY);
> +	if (fd < 0) {
> +		ksft_exit_skip("Failed to open " ALLOCINFO_PROC ": %s\n", strerror(errno));
> +		ret = KSFT_FAIL;
> +		goto freemem;
> +	}
> +
> +	do {
> +		found = false;
> +		pos = 0;
> +
> +		if (__allocinfo_get_content_id(fd, &start_cont_id)) {
> +			ksft_print_msg("allocinfo_get_content_id failed\n");
> +			ret = KSFT_FAIL;
> +			goto exit;
> +		}
> +
> +		memset(&filter, 0, sizeof(filter));
> +		filter.mask |= ALLOCINFO_FILTER_MASK_FUNCTION;
> +		strncpy(filter.fields.function, target_function, ALLOCINFO_STR_SIZE);
> +
> +		if (get_filtered_procfs_entries(procfs_entries, &filter, fd)) {
> +			ksft_print_msg("Error retrieving entries from " ALLOCINFO_PROC "\n");
> +			ret = KSFT_FAIL;
> +			goto exit;
> +		}
> +


As I mentioned for patch 5, the retry loop in test_size_filter calls

get_filtered_procfs_entries() which reads fd to EOF via fdopen/fgets.

If a module load triggers a retry, the second call to 
get_filtered_procfs_entries() gets EOF

immediately.

And Sashiko has also reported several minor issues.


Thanks

Best Regards

Hao

> +		if (procfs_entries->count == 0) {
> +			ksft_print_msg("Function %s not found in procfs\n", target_function);
> +			ret = KSFT_SKIP;
> +			goto exit;
> +		}
> +
> +		target_size = procfs_entries->tag[0].counter.bytes;
> +
> +		memset(&filter, 0, sizeof(filter));
> +		filter.mask |= ALLOCINFO_FILTER_MASK_MIN_SIZE | ALLOCINFO_FILTER_MASK_MAX_SIZE;
> +		filter.min_size = target_size;
> +		filter.max_size = target_size;
> +
> +		while (1) {
> +			struct allocinfo_get_at get_at_params;
> +
> +			memset(&get_at_params, 0, sizeof(get_at_params));
> +			memcpy(&get_at_params.filter, &filter, sizeof(filter));
> +			get_at_params.pos = pos;
> +
> +			if (__allocinfo_get_at(fd, &get_at_params))
> +				break;
> +
> +			tags->count = 0;
> +			memcpy(&tags->tag[tags->count++], &get_at_params.data,
> +			       sizeof(get_at_params.data));
> +
> +			while (tags->count < VEC_MAX_ENTRIES &&
> +			       __allocinfo_get_next(fd, &tags->tag[tags->count]) == 0)
> +				tags->count++;
> +
> +			for (i = 0; i < tags->count; i++) {
> +				if (strcmp(tags->tag[i].tag.function, target_function) == 0) {
> +					found = true;
> +					break;
> +				}
> +			}
> +
> +			if (found || tags->count < VEC_MAX_ENTRIES)
> +				break;
> +
> +			pos += tags->count;
> +		}
> +
> +		if (__allocinfo_get_content_id(fd, &end_cont_id)) {
> +			ksft_print_msg("allocinfo_get_content_id failed\n");
> +			ret = KSFT_FAIL;
> +			goto exit;
> +		}
> +
> +		if (start_cont_id.id == end_cont_id.id)
> +			break;
> +
> +		ksft_print_msg("Module load detected during size verification, retrying...\n");
> +	} while (retry++ < max_retries);
> +
> +	if (start_cont_id.id == end_cont_id.id && !found) {
> +		ksft_print_msg("Entry with function %s not found in IOCTL results\n",
> +			       target_function);
> +		ret = KSFT_FAIL;
> +	}
> +
> +exit:
> +	close(fd);
> +freemem:
> +	free(tags);
> +	free(procfs_entries);
> +	return ret;
> +}
> +
> +static int test_lineno_filter(void)
> +{
> +	int fd;
> +	struct allocinfo_tag_data_vec *tags = malloc(sizeof(*tags));
> +	struct allocinfo_tag_data_vec *procfs_entries = malloc(sizeof(*procfs_entries));
> +	struct allocinfo_filter filter;
> +	enum ioctl_ret ioctl_status;
> +	int ret = KSFT_PASS;
> +	__u64 target_lineno, i;
> +
> +	if (!tags || !procfs_entries) {
> +		ksft_print_msg("Memory allocation failed.\n");
> +		ret = KSFT_FAIL;
> +		goto freemem;
> +	}
> +
> +	fd = open(ALLOCINFO_PROC, O_RDONLY);
> +	if (fd < 0) {
> +		ksft_exit_skip("Failed to open " ALLOCINFO_PROC ": %s\n", strerror(errno));
> +		ret = KSFT_FAIL;
> +		goto freemem;
> +	}
> +
> +	memset(&filter, 0, sizeof(filter));
> +
> +	if (get_filtered_procfs_entries(procfs_entries, &filter, fd)) {
> +		ksft_print_msg("Error retrieving entries from " ALLOCINFO_PROC "\n");
> +		ret = KSFT_FAIL;
> +		goto exit;
> +	}
> +	if (procfs_entries->count == 0) {
> +		ksft_print_msg("Could not retrieve procfs entries\n");
> +		ret = KSFT_SKIP;
> +		goto exit;
> +	}
> +	/*
> +	 * We depend on the result of procfs entries to create the ioctl_filter. Hence we
> +	 * cannot recycle the run_filter_test function here.
> +	 */
> +	target_lineno = procfs_entries->tag[0].tag.lineno;
> +
> +	filter.mask |= ALLOCINFO_FILTER_MASK_LINENO;
> +	filter.fields.lineno = target_lineno;
> +
> +	ioctl_status = get_filtered_ioctl_entries(tags, &filter, fd, 0);
> +	if (ioctl_status == IOCTL_INVALID_DATA) {
> +		ksft_print_msg("Trouble retrieving valid IOCTL entries, skipping.\n");
> +		ret = KSFT_SKIP;
> +		goto exit;
> +	}
> +	if (ioctl_status == IOCTL_FAILURE) {
> +		ksft_print_msg("Error retrieving IOCTL entries.\n");
> +		ret = KSFT_FAIL;
> +		goto exit;
> +	}
> +
> +	for (i = 0; i < tags->count; i++) {
> +		if (tags->tag[i].tag.lineno != target_lineno) {
> +			ksft_print_msg("IOCTL entry %llu has incorrect lineno %llu.\n",
> +				       i, tags->tag[i].tag.lineno);
> +			ret = KSFT_FAIL;
> +			goto exit;
> +		}
> +	}
> +
> +exit:
> +	close(fd);
> +freemem:
> +	free(tags);
> +	free(procfs_entries);
> +	return ret;
> +}
> +
>   int main(int argc, char *argv[])
>   {
>   	int ret;
>   
> -	ksft_set_plan(2);
> +	ksft_set_plan(4);
>   
>   	ret = test_filename_filter();
>   	if (ret == KSFT_SKIP)
> @@ -329,5 +519,17 @@ int main(int argc, char *argv[])
>   	else
>   		ksft_test_result(ret == KSFT_PASS, "test_function_filter\n");
>   
> +	ret = test_size_filter();
> +	if (ret == KSFT_SKIP)
> +		ksft_test_result_skip("Skipping test_size_filter\n");
> +	else
> +		ksft_test_result(ret == KSFT_PASS, "test_size_filter\n");
> +
> +	ret = test_lineno_filter();
> +	if (ret == KSFT_SKIP)
> +		ksft_test_result_skip("Skipping test_lineno_filter\n");
> +	else
> +		ksft_test_result(ret == KSFT_PASS, "test_lineno_filter\n");
> +
>   	ksft_finished();
>   }