[PATCH v6 5/8] selftests/proc: add verbose more for tests to facilitate debugging

From: Suren Baghdasaryan
Date: Fri Jul 04 2025 - 02:08:58 EST


Add verbose mode to the proc tests to print debugging information.
Usage: proc-pid-vm -v

Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
tools/testing/selftests/proc/proc-maps-race.c | 159 ++++++++++++++++--
1 file changed, 146 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/proc/proc-maps-race.c b/tools/testing/selftests/proc/proc-maps-race.c
index 6acdafdac9db..5f912fedd6cf 100644
--- a/tools/testing/selftests/proc/proc-maps-race.c
+++ b/tools/testing/selftests/proc/proc-maps-race.c
@@ -39,6 +39,7 @@

static unsigned long test_duration_sec = 5UL;
static int page_size;
+static bool verbose;

/* /proc/pid/maps parsing routines */
struct page_content {
@@ -207,6 +208,99 @@ static void stop_vma_modifier(struct vma_modifier_info *mod_info)
signal_state(mod_info, SETUP_MODIFY_MAPS);
}

+static void print_first_lines(char *text, int nr)
+{
+ const char *end = text;
+
+ while (nr && (end = strchr(end, '\n')) != NULL) {
+ nr--;
+ end++;
+ }
+
+ if (end) {
+ int offs = end - text;
+
+ text[offs] = '\0';
+ printf(text);
+ text[offs] = '\n';
+ printf("\n");
+ } else {
+ printf(text);
+ }
+}
+
+static void print_last_lines(char *text, int nr)
+{
+ const char *start = text + strlen(text);
+
+ nr++; /* to ignore the last newline */
+ while (nr) {
+ while (start > text && *start != '\n')
+ start--;
+ nr--;
+ start--;
+ }
+ printf(start);
+}
+
+static void print_boundaries(const char *title,
+ struct page_content *page1,
+ struct page_content *page2)
+{
+ if (!verbose)
+ return;
+
+ printf("%s", title);
+ /* Print 3 boundary lines from each page */
+ print_last_lines(page1->data, 3);
+ printf("-----------------page boundary-----------------\n");
+ print_first_lines(page2->data, 3);
+}
+
+static bool print_boundaries_on(bool condition, const char *title,
+ struct page_content *page1,
+ struct page_content *page2)
+{
+ if (verbose && condition)
+ print_boundaries(title, page1, page2);
+
+ return condition;
+}
+
+static void report_test_start(const char *name)
+{
+ if (verbose)
+ printf("==== %s ====\n", name);
+}
+
+static struct timespec print_ts;
+
+static void start_test_loop(struct timespec *ts)
+{
+ if (verbose)
+ print_ts.tv_sec = ts->tv_sec;
+}
+
+static void end_test_iteration(struct timespec *ts)
+{
+ if (!verbose)
+ return;
+
+ /* Update every second */
+ if (print_ts.tv_sec == ts->tv_sec)
+ return;
+
+ printf(".");
+ fflush(stdout);
+ print_ts.tv_sec = ts->tv_sec;
+}
+
+static void end_test_loop(void)
+{
+ if (verbose)
+ printf("\n");
+}
+
static void capture_mod_pattern(int maps_fd,
struct vma_modifier_info *mod_info,
struct page_content *page1,
@@ -218,18 +312,24 @@ static void capture_mod_pattern(int maps_fd,
struct line_content *restored_last_line,
struct line_content *restored_first_line)
{
+ print_boundaries("Before modification", page1, page2);
+
signal_state(mod_info, SETUP_MODIFY_MAPS);
wait_for_state(mod_info, SETUP_MAPS_MODIFIED);

/* Copy last line of the first page and first line of the last page */
read_boundary_lines(maps_fd, page1, page2, mod_last_line, mod_first_line);

+ print_boundaries("After modification", page1, page2);
+
signal_state(mod_info, SETUP_RESTORE_MAPS);
wait_for_state(mod_info, SETUP_MAPS_RESTORED);

/* Copy last line of the first page and first line of the last page */
read_boundary_lines(maps_fd, page1, page2, restored_last_line, restored_first_line);

+ print_boundaries("After restore", page1, page2);
+
mod_info->vma_mod_check(mod_last_line, mod_first_line,
restored_last_line, restored_first_line);

@@ -301,6 +401,7 @@ static void test_maps_tearing_from_split(int maps_fd,
mod_info->vma_restore = merge_vma;
mod_info->vma_mod_check = check_split_result;

+ report_test_start("Tearing from split");
capture_mod_pattern(maps_fd, mod_info, page1, page2, last_line, first_line,
&split_last_line, &split_first_line,
&restored_last_line, &restored_first_line);
@@ -313,6 +414,7 @@ static void test_maps_tearing_from_split(int maps_fd,
struct timespec start_ts, end_ts;

clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts);
+ start_test_loop(&start_ts);
do {
bool last_line_changed;
bool first_line_changed;
@@ -332,12 +434,18 @@ static void test_maps_tearing_from_split(int maps_fd,
* In that case new first line will be the same as the
* last restored line.
*/
- assert(!strcmp(new_first_line.text, split_first_line.text) ||
- !strcmp(new_first_line.text, restored_last_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, split_first_line.text) &&
+ strcmp(new_first_line.text, restored_last_line.text),
+ "Split result invalid", page1, page2));
} else {
/* The vmas should be consistent with merge results */
- assert(!strcmp(new_last_line.text, restored_last_line.text) &&
- !strcmp(new_first_line.text, restored_first_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_last_line.text, restored_last_line.text),
+ "Merge result invalid", page1, page2));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, restored_first_line.text),
+ "Merge result invalid", page1, page2));
}
/*
* First and last lines should change in unison. If the last
@@ -362,7 +470,9 @@ static void test_maps_tearing_from_split(int maps_fd,
vma_end == split_first_line.end_addr));

clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
+ end_test_iteration(&end_ts);
} while (end_ts.tv_sec - start_ts.tv_sec < test_duration_sec);
+ end_test_loop();

/* Signal the modifyer thread to stop and wait until it exits */
signal_state(mod_info, TEST_DONE);
@@ -409,6 +519,7 @@ static void test_maps_tearing_from_resize(int maps_fd,
mod_info->vma_restore = expand_vma;
mod_info->vma_mod_check = check_shrink_result;

+ report_test_start("Tearing from resize");
capture_mod_pattern(maps_fd, mod_info, page1, page2, last_line, first_line,
&shrunk_last_line, &shrunk_first_line,
&restored_last_line, &restored_first_line);
@@ -421,6 +532,7 @@ static void test_maps_tearing_from_resize(int maps_fd,
struct timespec start_ts, end_ts;

clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts);
+ start_test_loop(&start_ts);
do {
unsigned long vma_start;
unsigned long vma_end;
@@ -437,12 +549,18 @@ static void test_maps_tearing_from_resize(int maps_fd,
* again. In that case new first line will be the same
* as the last restored line.
*/
- assert(!strcmp(new_first_line.text, shrunk_first_line.text) ||
- !strcmp(new_first_line.text, restored_last_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, shrunk_first_line.text) &&
+ strcmp(new_first_line.text, restored_last_line.text),
+ "Shrink result invalid", page1, page2));
} else {
/* The vmas should be consistent with the original/resored state */
- assert(!strcmp(new_last_line.text, restored_last_line.text) &&
- !strcmp(new_first_line.text, restored_first_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_last_line.text, restored_last_line.text),
+ "Expand result invalid", page1, page2));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, restored_first_line.text),
+ "Expand result invalid", page1, page2));
}

/* Check if PROCMAP_QUERY ioclt() finds the right VMA */
@@ -456,7 +574,9 @@ static void test_maps_tearing_from_resize(int maps_fd,
vma_end - vma_start == page_size));

clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
+ end_test_iteration(&end_ts);
} while (end_ts.tv_sec - start_ts.tv_sec < test_duration_sec);
+ end_test_loop();

/* Signal the modifyer thread to stop and wait until it exits */
signal_state(mod_info, TEST_DONE);
@@ -512,6 +632,7 @@ static void test_maps_tearing_from_remap(int maps_fd,
mod_info->vma_restore = patch_vma;
mod_info->vma_mod_check = check_remap_result;

+ report_test_start("Tearing from remap");
capture_mod_pattern(maps_fd, mod_info, page1, page2, last_line, first_line,
&remapped_last_line, &remapped_first_line,
&restored_last_line, &restored_first_line);
@@ -524,6 +645,7 @@ static void test_maps_tearing_from_remap(int maps_fd,
struct timespec start_ts, end_ts;

clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts);
+ start_test_loop(&start_ts);
do {
unsigned long vma_start;
unsigned long vma_end;
@@ -540,12 +662,18 @@ static void test_maps_tearing_from_remap(int maps_fd,
* again. In that case new first line will be the same
* as the last restored line.
*/
- assert(!strcmp(new_first_line.text, remapped_first_line.text) ||
- !strcmp(new_first_line.text, restored_last_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, remapped_first_line.text) &&
+ strcmp(new_first_line.text, restored_last_line.text),
+ "Remap result invalid", page1, page2));
} else {
/* The vmas should be consistent with the original/resored state */
- assert(!strcmp(new_last_line.text, restored_last_line.text) &&
- !strcmp(new_first_line.text, restored_first_line.text));
+ assert(!print_boundaries_on(
+ strcmp(new_last_line.text, restored_last_line.text),
+ "Remap restore result invalid", page1, page2));
+ assert(!print_boundaries_on(
+ strcmp(new_first_line.text, restored_first_line.text),
+ "Remap restore result invalid", page1, page2));
}

/* Check if PROCMAP_QUERY ioclt() finds the right VMA */
@@ -561,7 +689,9 @@ static void test_maps_tearing_from_remap(int maps_fd,
vma_end - vma_start == page_size));

clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
+ end_test_iteration(&end_ts);
} while (end_ts.tv_sec - start_ts.tv_sec < test_duration_sec);
+ end_test_loop();

/* Signal the modifyer thread to stop and wait until it exits */
signal_state(mod_info, TEST_DONE);
@@ -571,6 +701,7 @@ int usage(void)
{
fprintf(stderr, "Userland /proc/pid/{s}maps race test cases\n");
fprintf(stderr, " -d: Duration for time-consuming tests\n");
+ fprintf(stderr, " -v: Verbose mode\n");
fprintf(stderr, " -h: Help screen\n");
exit(-1);
}
@@ -588,9 +719,11 @@ int main(int argc, char **argv)
pid_t pid;
int opt;

- while ((opt = getopt(argc, argv, "d:h")) != -1) {
+ while ((opt = getopt(argc, argv, "d:vh")) != -1) {
if (opt == 'd')
test_duration_sec = strtoul(optarg, NULL, 0);
+ else if (opt == 'v')
+ verbose = true;
else if (opt == 'h')
usage();
}
--
2.50.0.727.gbf7dc18ff4-goog