1 files changed, 73 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 11d44a1e0ab3..632473beb40c 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -104,6 +104,68 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_
                                                 u64 end,
                                                 enum drm_mm_search_flags flags);
 
+#ifdef CONFIG_DRM_DEBUG_MM
+#include <linux/stackdepot.h>
+
+#define STACKDEPTH 32
+#define BUFSZ 4096
+
+static noinline void save_stack(struct drm_mm_node *node)
+{
+        unsigned long entries[STACKDEPTH];
+        struct stack_trace trace = {
+                .entries = entries,
+                .max_entries = STACKDEPTH,
+                .skip = 1
+        };
+
+        save_stack_trace(&trace);
+        if (trace.nr_entries != 0 &&
+            trace.entries[trace.nr_entries-1] == ULONG_MAX)
+                trace.nr_entries--;
+
+        /* May be called under spinlock, so avoid sleeping */
+        node->stack = depot_save_stack(&trace, GFP_NOWAIT);
+}
+
+static void show_leaks(struct drm_mm *mm)
+{
+        struct drm_mm_node *node;
+        unsigned long entries[STACKDEPTH];
+        char *buf;
+
+        buf = kmalloc(BUFSZ, GFP_KERNEL);
+        if (!buf)
+                return;
+
+        list_for_each_entry(node, &mm->head_node.node_list, node_list) {
+                struct stack_trace trace = {
+                        .entries = entries,
+                        .max_entries = STACKDEPTH
+                };
+
+                if (!node->stack) {
+                        DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
+                                  node->start, node->size);
+                        continue;
+                }
+
+                depot_fetch_stack(node->stack, &trace);
+                snprint_stack_trace(buf, BUFSZ, &trace, 0);
+                DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
+                          node->start, node->size, buf);
+        }
+
+        kfree(buf);
+}
+
+#undef STACKDEPTH
+#undef BUFSZ
+#else
+static void save_stack(struct drm_mm_node *node) { }
+static void show_leaks(struct drm_mm *mm) { }
+#endif
+
 #define START(node) ((node)->start)
 #define LAST(node)  ((node)->start + (node)->size - 1)
 
@@ -228,6 +290,8 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
                 list_add(&node->hole_stack, &mm->hole_stack);
                 node->hole_follows = 1;
         }
+
+        save_stack(node);
 }
 
 /**
@@ -293,6 +357,8 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
                 node->hole_follows = 1;
         }
 
+        save_stack(node);
+
         return 0;
 }
 EXPORT_SYMBOL(drm_mm_reserve_node);
@@ -397,6 +463,8 @@ static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
                 list_add(&node->hole_stack, &mm->hole_stack);
                 node->hole_follows = 1;
         }
+
+        save_stack(node);
 }
 
 /**
@@ -861,10 +929,12 @@ EXPORT_SYMBOL(drm_mm_init);
  * Note that it is a bug to call this function on an allocator which is not
  * clean.
  */
-void drm_mm_takedown(struct drm_mm * mm)
+void drm_mm_takedown(struct drm_mm *mm)
 {
-        WARN(!list_empty(&mm->head_node.node_list),
-             "Memory manager not clean during takedown.\n");
+        if (WARN(!list_empty(&mm->head_node.node_list),
+                 "Memory manager not clean during takedown.\n"))
+                show_leaks(mm);
+
 }
 EXPORT_SYMBOL(drm_mm_takedown);