damon_sysfs_set_targets() had a bug that can result in unexpected memory usage and monitoring overhead increase. The bug has fixed by a previous commit. Add a unit test for avoiding a similar bug of future.

Signed-off-by: SeongJae Park sj@kernel.org --- mm/damon/Kconfig | 12 ++++++ mm/damon/sysfs-test.h | 86 +++++++++++++++++++++++++++++++++++++++++++ mm/damon/sysfs.c | 2 + 3 files changed, 100 insertions(+) create mode 100644 mm/damon/sysfs-test.h

diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig index 436c6b4cb5ec..29f43fbc2eff 100644 --- a/mm/damon/Kconfig +++ b/mm/damon/Kconfig @@ -59,6 +59,18 @@ config DAMON_SYSFS This builds the sysfs interface for DAMON. The user space can use the interface for arbitrary data access monitoring.

+config DAMON_SYSFS_KUNIT_TEST + bool "Test for damon debugfs interface" if !KUNIT_ALL_TESTS + depends on DAMON_SYSFS && KUNIT=y + default KUNIT_ALL_TESTS + help + This builds the DAMON sysfs interface Kunit test suite. + + For more information on KUnit and unit tests in general, please refer + to the KUnit documentation. + + If unsure, say N. + config DAMON_DBGFS bool "DAMON debugfs interface (DEPRECATED!)" depends on DAMON_VADDR && DAMON_PADDR && DEBUG_FS diff --git a/mm/damon/sysfs-test.h b/mm/damon/sysfs-test.h new file mode 100644 index 000000000000..73bdce2452c1 --- /dev/null +++ b/mm/damon/sysfs-test.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Data Access Monitor Unit Tests + * + * Author: SeongJae Park sj@kernel.org + */ + +#ifdef CONFIG_DAMON_SYSFS_KUNIT_TEST + +#ifndef _DAMON_SYSFS_TEST_H +#define _DAMON_SYSFS_TEST_H + +#include <kunit/test.h> + +static unsigned int nr_damon_targets(struct damon_ctx *ctx) +{ + struct damon_target *t; + unsigned int nr_targets = 0; + + damon_for_each_target(t, ctx) + nr_targets++; + + return nr_targets; +} + +static int __damon_sysfs_test_get_any_pid(int min, int max) +{ + struct pid *pid; + int i; + + for (i = min; i <= max; i++) { + pid = find_get_pid(i); + if (pid) { + put_pid(pid); + return i; + } + } + return -1; +} + +static void damon_sysfs_test_set_targets(struct kunit *test) +{ + struct damon_sysfs_targets *sysfs_targets; + struct damon_sysfs_target *sysfs_target; + struct damon_ctx *ctx; + + sysfs_targets = damon_sysfs_targets_alloc(); + sysfs_targets->nr = 1; + sysfs_targets->targets_arr = kmalloc_array(1, + sizeof(*sysfs_targets->targets_arr), GFP_KERNEL); + + sysfs_target = damon_sysfs_target_alloc(); + sysfs_target->pid = __damon_sysfs_test_get_any_pid(12, 100); + sysfs_target->regions = damon_sysfs_regions_alloc(); + sysfs_targets->targets_arr[0] = sysfs_target; + + ctx = damon_new_ctx(); + + damon_sysfs_set_targets(ctx, sysfs_targets); + KUNIT_EXPECT_EQ(test, 1u, nr_damon_targets(ctx)); + + sysfs_target->pid = __damon_sysfs_test_get_any_pid( + sysfs_target->pid + 1, 200); + damon_sysfs_set_targets(ctx, sysfs_targets); + KUNIT_EXPECT_EQ(test, 1u, nr_damon_targets(ctx)); + + damon_destroy_ctx(ctx); + kfree(sysfs_targets->targets_arr); + kfree(sysfs_targets); + kfree(sysfs_target); +} + +static struct kunit_case damon_sysfs_test_cases[] = { + KUNIT_CASE(damon_sysfs_test_set_targets), + {}, +}; + +static struct kunit_suite damon_sysfs_test_suite = { + .name = "damon-sysfs", + .test_cases = damon_sysfs_test_cases, +}; +kunit_test_suite(damon_sysfs_test_suite); + +#endif /* _DAMON_SYSFS_TEST_H */ + +#endif /* CONFIG_DAMON_SYSFS_KUNIT_TEST */ diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index 5268e8503722..d13e353bee52 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1804,3 +1804,5 @@ static int __init damon_sysfs_init(void) return err; } subsys_initcall(damon_sysfs_init); + +#include "sysfs-test.h"