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Commit 5705670d authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm: Track drm_mm allocators and show leaks on shutdown 



We can use the kernel's stack tracer and depot to record the allocation
site of every drm_mm user. Then on shutdown, as well as warning that
allocated nodes still reside with the drm_mm range manager, we can
display who allocated them to aide tracking down the leak.

v2: Move Kconfig around so it lies underneath the DRM options submenu.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161031090806.20073-1-chris@chris-wilson.co.uk
parent 55edf41b

drivers/gpu/drm/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -33,6 +33,19 @@ config DRM_DP_AUX_CHARDEV 
	  read and write values to arbitrary DPCD registers on the DP aux

	  channel.



config DRM_DEBUG_MM

	bool "Insert extra checks and debug info into the DRM range managers"

	default n

	depends on DRM

	select STACKDEPOT

	help

	  Enable allocation tracking of memory manager and leak detection on

	  shutdown.



	  Recommended for driver developers only.



	  If in doubt, say "N".



config DRM_KMS_HELPER

	tristate

	depends on DRM

drivers/gpu/drm/drm_mm.c

+71 −3
Original line number Diff line number Diff line
@@ -104,6 +104,66 @@ 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

#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 +288,8 @@ 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 +355,8 @@ 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 +461,8 @@ 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);

}



/**
@@ -863,8 +929,10 @@ EXPORT_SYMBOL(drm_mm_init); 
 */

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);

include/drm/drm_mm.h

+6 −0
Original line number Diff line number Diff line
@@ -44,6 +44,9 @@ 
#ifdef CONFIG_DEBUG_FS

#include <linux/seq_file.h>

#endif

#ifdef CONFIG_DRM_DEBUG_MM

#include <linux/stackdepot.h>

#endif



enum drm_mm_search_flags {

	DRM_MM_SEARCH_DEFAULT =		0,
@@ -74,6 +77,9 @@ struct drm_mm_node { 
	u64 size;

	u64 __subtree_last;

	struct drm_mm *mm;

#ifdef CONFIG_DRM_DEBUG_MM

	depot_stack_handle_t stack;

#endif

};



struct drm_mm {