From 5705670d0463423337c82d00877989e7df8b169d Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 31 Oct 2016 09:08:06 +0000 Subject: [PATCH] drm: Track drm_mm allocators and show leaks on shutdown MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Chris Wilson Reviewed-by: Christian König Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161031090806.20073-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/Kconfig | 13 +++++++ drivers/gpu/drm/drm_mm.c | 74 ++++++++++++++++++++++++++++++++++++++-- include/drm/drm_mm.h | 6 ++++ 3 files changed, 90 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 483059a22b1b..25e8e3793d29 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -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 diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index 11d44a1e0ab3..89b891a4847f 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -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); } /** @@ -861,10 +927,12 @@ 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); diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h index 205ddcf6d55d..41ddafe92b2f 100644 --- a/include/drm/drm_mm.h +++ b/include/drm/drm_mm.h @@ -44,6 +44,9 @@ #ifdef CONFIG_DEBUG_FS #include #endif +#ifdef CONFIG_DRM_DEBUG_MM +#include +#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 {