kselftest: alloc_tag: extend the allocinfo ioctl kselftest

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.

Link: https://lore.kernel.org/e5171926b48802531284c1cb5f04734017141341.1783532853.git.abhishekbapat@google.com
Signed-off-by: Abhishek Bapat <abhishekbapat@google.com>
Tested-by: Hao Ge <hao.ge@linux.dev>
Acked-by: Hao Ge <hao.ge@linux.dev>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 215 insertions, 1 deletions

diff --git a/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c b/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
index 3614ee9b46fb..74fd64b2370c 100644
--- a/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
+++ b/tools/testing/selftests/alloc_tag/allocinfo_ioctl_test.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2026 Google, Inc.
  */
 
+#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -312,11 +313,212 @@ 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;
+	struct allocinfo_tag_data *found_tag = NULL;
+	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_print_msg("Failed to open " ALLOCINFO_PROC ": %s\n", strerror(errno));
+		ret = KSFT_SKIP;
+		goto freemem;
+	}
+
+	do {
+		found_tag = NULL;
+		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)) {
+			ksft_print_msg("Error retrieving entries from " ALLOCINFO_PROC "\n");
+			ret = KSFT_SKIP;
+			goto exit;
+		}
+
+		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_tag = &tags->tag[i];
+					break;
+				}
+			}
+
+			if (found_tag || 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_tag) {
+		ksft_print_msg("Entry with function %s not found in IOCTL results\n",
+			       target_function);
+		ret = KSFT_FAIL;
+	} else if (start_cont_id.id != end_cont_id.id) {
+		ksft_print_msg("Failed to match content_ids for procfs and IOCTL, skipping...\n");
+		ret = KSFT_SKIP;
+	} else if (found_tag && found_tag->counter.bytes != target_size) {
+		ksft_print_msg("IOCTL entry size %llu does not match target size %llu\n",
+			       found_tag->counter.bytes, target_size);
+		ret = KSFT_FAIL;
+	}
+
+exit:
+	close(fd);
+freemem:
+	free(tags);
+	free(procfs_entries);
+	return ret;
+}
+
+static int test_lineno_filter(void)
+{
+	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;
+	struct allocinfo_tag_data *target_tag;
+	bool found = false;
+
+	if (!tags || !procfs_entries) {
+		ksft_print_msg("Memory allocation failed.\n");
+		ret = KSFT_FAIL;
+		goto exit;
+	}
+
+	memset(&filter, 0, sizeof(filter));
+
+	if (get_filtered_procfs_entries(procfs_entries, &filter)) {
+		ksft_print_msg("Error retrieving entries from " ALLOCINFO_PROC "\n");
+		ret = KSFT_SKIP;
+		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 procfs results to determine the line number for the filter before
+	 * making the ioctl query. Hence, we cannot reuse run_filter_test here.
+	 */
+	target_tag = &procfs_entries->tag[0];
+	target_lineno = target_tag->tag.lineno;
+
+	filter.mask |= ALLOCINFO_FILTER_MASK_LINENO;
+	filter.fields.lineno = target_lineno;
+
+	ioctl_status = get_filtered_ioctl_entries(tags, &filter, 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;
+		}
+
+		if (strncmp(tags->tag[i].tag.function, target_tag->tag.function,
+			    ALLOCINFO_STR_SIZE) == 0 &&
+		    strncmp(tags->tag[i].tag.filename, target_tag->tag.filename,
+			    ALLOCINFO_STR_SIZE) == 0)
+			found = true;
+	}
+
+	if (!found) {
+		ksft_print_msg("Original procfs entry not found in IOCTL lineno filter results.\n");
+		ret = KSFT_FAIL;
+	}
+
+exit:
+	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)
@@ -330,5 +532,17 @@ 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();
 }