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| author | SeongJae Park <sj@kernel.org> | 2024-02-07 23:31:32 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-22 21:24:56 +0300 |
| commit | e6255a297628ddd7ead9cf8fb2ce11168595c89d (patch) | |
| tree | 5450697d2e1612c82dc22189cf294e1b00b70559 /tools/testing/selftests/damon | |
| parent | ce7a2834659fd18eda042574696fe4191f069e31 (diff) | |
| download | linux-e6255a297628ddd7ead9cf8fb2ce11168595c89d.tar.xz | |
selftests/damon: add a test for a race between target_ids_read() and dbgfs_before_terminate()
commit 34796417964b ("mm/damon/dbgfs: protect targets destructions with
kdamond_lock") fixed a race of DAMON debugfs interface. Specifically, the
race was happening between target_ids_read() and dbgfs_before_terminate().
Add a test for the issue to prevent the problem from accidentally
recurring.
Link: https://lkml.kernel.org/r/20240207203134.69976-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools/testing/selftests/damon')
4 files changed, 97 insertions, 0 deletions
diff --git a/tools/testing/selftests/damon/.gitignore b/tools/testing/selftests/damon/.gitignore index c6c2965a6607..7d6c6e062be7 100644 --- a/tools/testing/selftests/damon/.gitignore +++ b/tools/testing/selftests/damon/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only huge_count_read_write +debugfs_target_ids_read_before_terminate_race diff --git a/tools/testing/selftests/damon/Makefile b/tools/testing/selftests/damon/Makefile index b545fedafb3b..8a3a8df003db 100644 --- a/tools/testing/selftests/damon/Makefile +++ b/tools/testing/selftests/damon/Makefile @@ -2,6 +2,7 @@ # Makefile for damon selftests TEST_GEN_FILES += huge_count_read_write +TEST_GEN_FILES += debugfs_target_ids_read_before_terminate_race TEST_GEN_FILES += access_memory TEST_FILES = _chk_dependency.sh _debugfs_common.sh @@ -9,6 +10,7 @@ TEST_PROGS = debugfs_attrs.sh debugfs_schemes.sh debugfs_target_ids.sh TEST_PROGS += debugfs_empty_targets.sh debugfs_huge_count_read_write.sh TEST_PROGS += debugfs_duplicate_context_creation.sh TEST_PROGS += debugfs_rm_non_contexts.sh +TEST_PROGS += debugfs_target_ids_read_before_terminate_race.sh TEST_PROGS += sysfs.sh sysfs_update_removed_scheme_dir.sh TEST_PROGS += sysfs_update_schemes_tried_regions_hang.py TEST_PROGS += sysfs_update_schemes_tried_regions_wss_estimation.py diff --git a/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.c b/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.c new file mode 100644 index 000000000000..b06f52a8ce2d --- /dev/null +++ b/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Author: SeongJae Park <sj@kernel.org> + */ +#define _GNU_SOURCE + +#include <fcntl.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <time.h> +#include <unistd.h> + +#define DBGFS_MONITOR_ON "/sys/kernel/debug/damon/monitor_on_DEPRECATED" +#define DBGFS_TARGET_IDS "/sys/kernel/debug/damon/target_ids" + +static void turn_damon_on_exit(void) +{ + int target_ids_fd = open(DBGFS_TARGET_IDS, O_RDWR); + int monitor_on_fd = open(DBGFS_MONITOR_ON, O_RDWR); + char pid_str[128]; + + snprintf(pid_str, sizeof(pid_str), "%d", getpid()); + write(target_ids_fd, pid_str, sizeof(pid_str)); + write(monitor_on_fd, "on\n", 3); + close(target_ids_fd); + close(monitor_on_fd); + usleep(1000); + exit(0); +} + +static void try_race(void) +{ + int target_ids_fd = open(DBGFS_TARGET_IDS, O_RDWR); + int pid = fork(); + int buf[256]; + + if (pid < 0) { + fprintf(stderr, "fork() failed\n"); + exit(1); + } + if (pid == 0) + turn_damon_on_exit(); + while (true) { + int status; + + read(target_ids_fd, buf, sizeof(buf)); + if (waitpid(-1, &status, WNOHANG) == pid) + break; + } + close(target_ids_fd); +} + +static inline uint64_t ts_to_ms(struct timespec *ts) +{ + return (uint64_t)ts->tv_sec * 1000 + (uint64_t)ts->tv_nsec / 1000000; +} + +int main(int argc, char *argv[]) +{ + struct timespec start_time, now; + int runtime_ms; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <runtime in ms>\n", argv[0]); + exit(1); + } + runtime_ms = atoi(argv[1]); + clock_gettime(CLOCK_MONOTONIC, &start_time); + while (true) { + try_race(); + clock_gettime(CLOCK_MONOTONIC, &now); + if (ts_to_ms(&now) - ts_to_ms(&start_time) > runtime_ms) + break; + } + return 0; +} diff --git a/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.sh b/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.sh new file mode 100644 index 000000000000..fc793c4c9aea --- /dev/null +++ b/tools/testing/selftests/damon/debugfs_target_ids_read_before_terminate_race.sh @@ -0,0 +1,14 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +dmesg -C + +./debugfs_target_ids_read_before_terminate_race 5000 + +if dmesg | grep -q dbgfs_target_ids_read +then + dmesg + exit 1 +else + exit 0 +fi |