[PATCH i-g-t] lib/igt_list: igt_list_empty() Detect uninitialized list

[Peter Senna Tschudin <peter.senna@linux.intel.com>]

Add a check to igt_list_empty() to return true if the list head pointer
or its next/prev pointers are NULL, preventing segfaults when operating
on uninitialized or potentially broken lists.

Signed-off-by: Peter Senna Tschudin <peter.senna@linux.intel.com>
---
 lib/igt_list.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/igt_list.c b/lib/igt_list.c
index 37ae139c4..f77aef7dd 100644
--- a/lib/igt_list.c
+++ b/lib/igt_list.c
@@ -79,5 +79,9 @@ int igt_list_length(const struct igt_list_head *head)
 
 bool igt_list_empty(const struct igt_list_head *head)
 {
+	/* Detect uninitialized / potentially broken list */
+	if (!head || !head->next || !head->prev)
+		return true;
+
 	return head->next == head;
 }
-- 
2.43.0