[PATCH 0/2] KUnit-Kmemleak Integration

[PATCH 0/2] KUnit-Kmemleak Integration

[Uriel Guajardo]

From: Uriel Guajardo <urielguajardo@google.com>

With these patches, KUnit can access and manually run kmemleak in every test
case. Any errors caught by kmemleak will cause the KUnit test to fail.

This patchset relies on "kunit: KASAN integration", which places the
currently running kunit test in task_struct. [1]

[1] https://lore.kernel.org/linux-kselftest/20200606040349.246780-2-davidgow@google.com

Uriel Guajardo (2):
  kunit: support kunit failures from debugging tools
  kunit: kmemleak integration

 include/kunit/test-bug.h | 15 +++++++++++++
 include/kunit/test.h     |  1 +
 include/linux/kmemleak.h | 11 ++++++++++
 lib/Kconfig.debug        | 26 +++++++++++++++++++++++
 lib/kunit/test.c         | 46 +++++++++++++++++++++++++++++++++++-----
 mm/kmemleak.c            | 27 +++++++++++++++++------
 6 files changed, 115 insertions(+), 11 deletions(-)
 create mode 100644 include/kunit/test-bug.h

-- 
2.27.0.212.ge8ba1cc988-goog

[PATCH 1/2] kunit: support kunit failures from debugging tools

[Uriel Guajardo]

From: Uriel Guajardo <urielguajardo@google.com>

Dynamic analyis tools can now fail the currently running kunit
test case by calling kunit_fail_current_test().

A new header file is created so that no circular dependencies are
created with external tools.

This patch requires "kunit: KASAN integration", which places the
currently running kunit test in task_struct. [1]

[1] https://lore.kernel.org/linux-kselftest/20200606040349.246780-2-davidgow@google.com

Signed-off-by: Uriel Guajardo <urielguajardo@google.com>
---
 include/kunit/test-bug.h | 15 +++++++++++++++
 include/kunit/test.h     |  1 +
 lib/kunit/test.c         | 10 ++++++----
 3 files changed, 22 insertions(+), 4 deletions(-)
 create mode 100644 include/kunit/test-bug.h

diff --git a/include/kunit/test-bug.h b/include/kunit/test-bug.h
new file mode 100644
index 000000000000..69ec3dd91c52
--- /dev/null
+++ b/include/kunit/test-bug.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Base unit test (KUnit) API.
+ *
+ * Copyright (C) 2020, Google LLC.
+ * Author: Uriel Guajardo <urielguajardo@google.com>
+ */
+
+#if IS_ENABLED(CONFIG_KUNIT)
+extern void kunit_fail_current_test(void);
+#else
+static inline void kunit_fail_current_test(void)
+{
+}
+#endif
diff --git a/include/kunit/test.h b/include/kunit/test.h
index 1dc3d118f64b..c46715c739b5 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -11,6 +11,7 @@
 
 #include <kunit/assert.h>
 #include <kunit/try-catch.h>
+#include <kunit/test-bug.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index ef3bfb9fae48..8580ed831a8f 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -16,6 +16,12 @@
 #include "string-stream.h"
 #include "try-catch-impl.h"
 
+void kunit_fail_current_test(void)
+{
+	if (current->kunit_test)
+		kunit_set_failure(current->kunit_test);
+}
+
 static void kunit_print_tap_version(void)
 {
 	static bool kunit_has_printed_tap_version;
@@ -284,9 +290,7 @@ static void kunit_try_run_case(void *data)
 	struct kunit_suite *suite = ctx->suite;
 	struct kunit_case *test_case = ctx->test_case;
 
-#if (IS_ENABLED(CONFIG_KASAN) && IS_ENABLED(CONFIG_KUNIT))
 	current->kunit_test = test;
-#endif /* IS_ENABLED(CONFIG_KASAN) && IS_ENABLED(CONFIG_KUNIT) */
 
 	/*
 	 * kunit_run_case_internal may encounter a fatal error; if it does,
@@ -603,9 +607,7 @@ void kunit_cleanup(struct kunit *test)
 		spin_unlock(&test->lock);
 		kunit_remove_resource(test, res);
 	}
-#if (IS_ENABLED(CONFIG_KASAN) && IS_ENABLED(CONFIG_KUNIT))
 	current->kunit_test = NULL;
-#endif /* IS_ENABLED(CONFIG_KASAN) && IS_ENABLED(CONFIG_KUNIT)*/
 }
 EXPORT_SYMBOL_GPL(kunit_cleanup);
 
-- 
2.27.0.212.ge8ba1cc988-goog

[PATCH 2/2] kunit: kmemleak integration

[Uriel Guajardo]

From: Uriel Guajardo <urielguajardo@google.com>

Integrate kmemleak into the KUnit testing framework.

Kmemleak will now fail the currently running KUnit test case if it finds
any memory leaks.

The minimum object age for reporting is set to 0 msecs so that leaks are
not ignored if the test case finishes too quickly.

Signed-off-by: Uriel Guajardo <urielguajardo@google.com>
---
 include/linux/kmemleak.h | 11 +++++++++++
 lib/Kconfig.debug        | 26 ++++++++++++++++++++++++++
 lib/kunit/test.c         | 36 +++++++++++++++++++++++++++++++++++-
 mm/kmemleak.c            | 27 +++++++++++++++++++++------
 4 files changed, 93 insertions(+), 7 deletions(-)

diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
index 34684b2026ab..0da427934462 100644
--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -35,6 +35,10 @@ extern void kmemleak_free_part_phys(phys_addr_t phys, size_t size) __ref;
 extern void kmemleak_not_leak_phys(phys_addr_t phys) __ref;
 extern void kmemleak_ignore_phys(phys_addr_t phys) __ref;
 
+extern ssize_t kmemleak_write(struct file *file,
+			      const char __user *user_buf,
+			      size_t size, loff_t *ppos);
+
 static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
 					    int min_count, slab_flags_t flags,
 					    gfp_t gfp)
@@ -120,6 +124,13 @@ static inline void kmemleak_ignore_phys(phys_addr_t phys)
 {
 }
 
+static inline ssize_t kmemleak_write(struct file *file,
+				     const char __user *user_buf,
+				     size_t size, loff_t *ppos)
+{
+	return -1;
+}
+
 #endif	/* CONFIG_DEBUG_KMEMLEAK */
 
 #endif	/* __KMEMLEAK_H */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 21d9c5f6e7ec..e9c492cb3f4d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -602,6 +602,32 @@ config DEBUG_KMEMLEAK_MEM_POOL_SIZE
 	  fully initialised, this memory pool acts as an emergency one
 	  if slab allocations fail.
 
+config DEBUG_KMEMLEAK_MAX_TRACE
+	int "Kmemleak stack trace length"
+	depends on DEBUG_KMEMLEAK
+	default 16
+
+config DEBUG_KMEMLEAK_MSECS_MIN_AGE
+	int "Minimum object age before reporting in msecs"
+	depends on DEBUG_KMEMLEAK
+	default 0 if KUNIT
+	default 5000
+
+config DEBUG_KMEMLEAK_SECS_FIRST_SCAN
+	int "Delay before first scan in secs"
+	depends on DEBUG_KMEMLEAK
+	default 60
+
+config DEBUG_KMEMLEAK_SECS_SCAN_WAIT
+	int "Delay before subsequent auto scans in secs"
+	depends on DEBUG_KMEMLEAK
+	default 600
+
+config DEBUG_KMEMLEAK_MAX_SCAN_SIZE
+	int "Maximum size of scanned block"
+	depends on DEBUG_KMEMLEAK
+	default 4096
+
 config DEBUG_KMEMLEAK_TEST
 	tristate "Simple test for the kernel memory leak detector"
 	depends on DEBUG_KMEMLEAK && m
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 8580ed831a8f..8d113a6a214b 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -11,6 +11,7 @@
 #include <linux/kref.h>
 #include <linux/sched/debug.h>
 #include <linux/sched.h>
+#include <linux/kmemleak.h>
 
 #include "debugfs.h"
 #include "string-stream.h"
@@ -277,6 +278,27 @@ static void kunit_run_case_cleanup(struct kunit *test,
 	kunit_case_internal_cleanup(test);
 }
 
+/*
+ * Manually scans for memory leaks using the kmemleak tool.
+ *
+ * Any leaks that occurred since the previous scan will be
+ * reported and will cause the currently running test to fail.
+ */
+static inline void kmemleak_scan(void)
+{
+	loff_t pos;
+	kmemleak_write(NULL, "scan", 5, &pos);
+}
+
+/*
+ * Turn off the background automatic scan that kmemleak performs upon starting
+ */
+static inline void kmemleak_automatic_scan_off(void)
+{
+	loff_t pos;
+	kmemleak_write(NULL, "scan=off", 9, &pos);
+}
+
 struct kunit_try_catch_context {
 	struct kunit *test;
 	struct kunit_suite *suite;
@@ -290,6 +312,12 @@ static void kunit_try_run_case(void *data)
 	struct kunit_suite *suite = ctx->suite;
 	struct kunit_case *test_case = ctx->test_case;
 
+	/*
+	 * Clear any reported memory leaks since last scan, so that only the
+	 * leaks pertaining to the test case remain afterwards.
+	 */
+	kmemleak_scan();
+
 	current->kunit_test = test;
 
 	/*
@@ -298,7 +326,12 @@ static void kunit_try_run_case(void *data)
 	 * thread will resume control and handle any necessary clean up.
 	 */
 	kunit_run_case_internal(test, suite, test_case);
-	/* This line may never be reached. */
+
+	/* These lines may never be reached. */
+
+	/* Report any detected memory leaks that occurred in the test case */
+	kmemleak_scan();
+
 	kunit_run_case_cleanup(test, suite);
 }
 
@@ -388,6 +421,7 @@ static void kunit_init_suite(struct kunit_suite *suite)
 int __kunit_test_suites_init(struct kunit_suite **suites)
 {
 	unsigned int i;
+	kmemleak_automatic_scan_off();
 
 	for (i = 0; suites[i] != NULL; i++) {
 		kunit_init_suite(suites[i]);
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index e362dc3d2028..ad046c77e00c 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -99,15 +99,26 @@
 #include <linux/kasan.h>
 #include <linux/kmemleak.h>
 #include <linux/memory_hotplug.h>
+#include <kunit/test.h>
 
 /*
  * Kmemleak configuration and common defines.
  */
-#define MAX_TRACE		16	/* stack trace length */
-#define MSECS_MIN_AGE		5000	/* minimum object age for reporting */
-#define SECS_FIRST_SCAN		60	/* delay before the first scan */
-#define SECS_SCAN_WAIT		600	/* subsequent auto scanning delay */
-#define MAX_SCAN_SIZE		4096	/* maximum size of a scanned block */
+
+/* stack trace length */
+#define MAX_TRACE		CONFIG_DEBUG_KMEMLEAK_MAX_TRACE
+
+/* minimum object age for reporting */
+#define MSECS_MIN_AGE		CONFIG_DEBUG_KMEMLEAK_MSECS_MIN_AGE
+
+/* delay before the first scan */
+#define SECS_FIRST_SCAN		CONFIG_DEBUG_KMEMLEAK_SECS_FIRST_SCAN
+
+/* subsequent auto scanning delay */
+#define SECS_SCAN_WAIT		CONFIG_DEBUG_KMEMLEAK_SECS_SCAN_WAIT
+
+/* maximum size of a scanned lock */
+#define MAX_SCAN_SIZE		CONFIG_DEBUG_KMEMLEAK_MAX_SCAN_SIZE
 
 #define BYTES_PER_POINTER	sizeof(void *)
 
@@ -1490,6 +1501,7 @@ static void kmemleak_scan(void)
 	 * Check for new or unreferenced objects modified since the previous
 	 * scan and color them gray until the next scan.
 	 */
+#if (!IS_ENABLED(CONFIG_KUNIT))
 	rcu_read_lock();
 	list_for_each_entry_rcu(object, &object_list, object_list) {
 		raw_spin_lock_irqsave(&object->lock, flags);
@@ -1502,6 +1514,7 @@ static void kmemleak_scan(void)
 		raw_spin_unlock_irqrestore(&object->lock, flags);
 	}
 	rcu_read_unlock();
+#endif
 
 	/*
 	 * Re-scan the gray list for modified unreferenced objects.
@@ -1534,6 +1547,8 @@ static void kmemleak_scan(void)
 	rcu_read_unlock();
 
 	if (new_leaks) {
+		kunit_fail_current_test();
+
 		kmemleak_found_leaks = true;
 
 		pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
@@ -1764,7 +1779,7 @@ static void __kmemleak_do_cleanup(void);
  *		  if kmemleak has been disabled.
  *   dump=...	- dump information about the object found at the given address
  */
-static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
+ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
 			      size_t size, loff_t *ppos)
 {
 	char buf[64];
-- 
2.27.0.212.ge8ba1cc988-goog

[PATCH 0/2] KUnit-Kmemleak Integration

[Uriel Guajardo]

From: Uriel Guajardo <urielguajardo@google.com>

With these patches, KUnit can access and manually run kmemleak in every test
case. Any errors caught by kmemleak will cause the KUnit test to fail.

This patchset relies on "kunit: KASAN integration", which places the
currently running kunit test in task_struct. [1]

[1] https://lore.kernel.org/linux-kselftest/20200606040349.246780-2-davidgow@google.com

Uriel Guajardo (2):
  kunit: support kunit failures from debugging tools
  kunit: kmemleak integration

 include/kunit/test-bug.h | 15 +++++++++++++
 include/kunit/test.h     |  1 +
 include/linux/kmemleak.h | 11 ++++++++++
 lib/Kconfig.debug        | 26 +++++++++++++++++++++++
 lib/kunit/test.c         | 46 +++++++++++++++++++++++++++++++++++-----
 mm/kmemleak.c            | 27 +++++++++++++++++------
 6 files changed, 115 insertions(+), 11 deletions(-)
 create mode 100644 include/kunit/test-bug.h

-- 
2.27.0.212.ge8ba1cc988-goog