Thread (30 messages) 30 messages, 3 authors, 2025-09-25
STALE268d

[PATCH v5 19/23] mm/ksw: add recursive depth test

From: Jinchao Wang <hidden>
Date: 2025-09-24 12:00:33
Also in: linux-doc, linux-mm, linux-perf-users, lkml, llvm, workflows
Subsystem: memory management, the rest · Maintainers: Andrew Morton, Linus Torvalds

Introduce a test that performs stack writes in recursive calls to exercise
stack watch at a specific recursion depth.

Signed-off-by: Jinchao Wang <redacted>
---
 mm/kstackwatch/test.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c
index 740e3c11b3ef..08e3d37c4c04 100644
--- a/mm/kstackwatch/test.c
+++ b/mm/kstackwatch/test.c
@@ -57,6 +57,20 @@ static void test_canary_overflow(void)
 	pr_info("exit of %s\n", __func__);
 }
 
+static void test_recursive_depth(int depth)
+{
+	u64 buffer[BUFFER_SIZE];
+
+	pr_info("entry of %s depth:%d\n", __func__, depth);
+
+	if (depth < MAX_DEPTH)
+		test_recursive_depth(depth + 1);
+
+	buffer[0] = depth;
+	barrier_data(buffer);
+
+	pr_info("exit of %s depth:%d\n", __func__, depth);
+}
 
 static ssize_t test_proc_write(struct file *file, const char __user *buffer,
 			       size_t count, loff_t *pos)
@@ -83,6 +97,9 @@ static ssize_t test_proc_write(struct file *file, const char __user *buffer,
 		case 1:
 			test_canary_overflow();
 			break;
+		case 2:
+			test_recursive_depth(0);
+			break;
 		default:
 			pr_err("Unknown test number %d\n", test_num);
 			return -EINVAL;
@@ -103,7 +120,8 @@ static ssize_t test_proc_read(struct file *file, char __user *buffer,
 				    "Usage:\n"
 				    "echo test{i} > /proc/kstackwatch_test\n"
 				    " test0 - test watch fire\n"
-				    " test1 - test canary overflow\n";
+				    " test1 - test canary overflow\n"
+				    " test2 - test recursive func\n";
 
 	return simple_read_from_buffer(buffer, count, pos, usage,
 				       strlen(usage));
-- 
2.43.0
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