[PATCH v4 18/21] mm/ksw: add recursive stack corruption test

Jinchao Wang
2025-09-12T10:13:28Z

Add a test that triggers stack writes across recursive calls,verifying
detection at specific recursion depths.

Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
---
mm/kstackwatch/test.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c
index 2b196f72ffd7..3e867d778e91 100644
--- a/mm/kstackwatch/test.c
+++ b/mm/kstackwatch/test.c
@@ -150,6 +150,27 @@ static void silent_corruption_test(void)
silent_corruption_victim(i);
}

+/*
+ * Test Case 3: Recursive Call Corruption
+ * Test corruption detection at specified recursion depth
+ */
+static void recursive_corruption_test(int depth)
+{
+ u64 buffer[BUFFER_SIZE];
+
+ pr_info("recursive call at depth %d\n", depth);
+ pr_info("buffer 0x%lx\n", (unsigned long)buffer);
+ if (depth <= MAX_DEPTH)
+ recursive_corruption_test(depth + 1);
+
+ buffer[0] = depth;
+
+ /* make sure the compiler do not drop assign action */
+ barrier_data(buffer);
+
+ pr_info("returning from depth %d\n", depth);
+}
+
static ssize_t test_proc_write(struct file *file, const char __user *buffer,
size_t count, loff_t *pos)
{
@@ -181,6 +202,11 @@ static ssize_t test_proc_write(struct file *file, const char __user *buffer,
pr_info("triggering silent corruption test\n");
silent_corruption_test();
break;
+ case 3:
+ pr_info("triggering recursive corruption test\n");
+ /* depth start with 0 */
+ recursive_corruption_test(0);
+ break;
default:
pr_err("Unknown test number %d\n", test_num);
return -EINVAL;
@@ -202,7 +228,8 @@ static ssize_t test_proc_read(struct file *file, char __user *buffer,
"Usage:\n"
" echo 'test0' > /proc/kstackwatch_test - Canary write test\n"
" echo 'test1' > /proc/kstackwatch_test - Canary overflow test\n"
- " echo 'test2' > /proc/kstackwatch_test - Silent corruption test\n";
+ " echo 'test2' > /proc/kstackwatch_test - Silent corruption test\n"
+ " echo 'test3' > /proc/kstackwatch_test - Recursive corruption test\n";

return simple_read_from_buffer(buffer, count, pos, usage,
strlen(usage));
--
2.43.0