[Intel-gfx] [PATCH] drm: fix deadlock of syncobj v5
Chunming Zhou
david1.zhou at amd.com
Tue Oct 23 07:57:54 UTC 2018
v2:
add a mutex between sync_cb execution and free.
v3:
clearly separating the roles for pt_lock and cb_mutex (Chris)
v4:
the cb_mutex should be taken outside of the pt_lock around this if() block. (Chris)
v5:
fix a corner case
Tested by syncobj_basic and syncobj_wait of igt.
Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Christian König <christian.koenig at amd.com>
Cc: intel-gfx at lists.freedesktop.org
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/drm_syncobj.c | 55 +++++++++++++++++++----------------
include/drm/drm_syncobj.h | 8 +++--
2 files changed, 36 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 57bf6006394d..679a56791e34 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -125,23 +125,26 @@ static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
if (!ret)
return 1;
- spin_lock(&syncobj->lock);
+ mutex_lock(&syncobj->cb_mutex);
/* We've already tried once to get a fence and failed. Now that we
* have the lock, try one more time just to be sure we don't add a
* callback when a fence has already been set.
*/
+ spin_lock(&syncobj->pt_lock);
if (!list_empty(&syncobj->signal_pt_list)) {
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
drm_syncobj_search_fence(syncobj, 0, 0, fence);
- if (*fence)
+ if (*fence) {
+ mutex_unlock(&syncobj->cb_mutex);
return 1;
- spin_lock(&syncobj->lock);
+ }
} else {
+ spin_unlock(&syncobj->pt_lock);
*fence = NULL;
drm_syncobj_add_callback_locked(syncobj, cb, func);
ret = 0;
}
- spin_unlock(&syncobj->lock);
+ mutex_unlock(&syncobj->cb_mutex);
return ret;
}
@@ -150,43 +153,43 @@ void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
struct drm_syncobj_cb *cb,
drm_syncobj_func_t func)
{
- spin_lock(&syncobj->lock);
+ mutex_lock(&syncobj->cb_mutex);
drm_syncobj_add_callback_locked(syncobj, cb, func);
- spin_unlock(&syncobj->lock);
+ mutex_unlock(&syncobj->cb_mutex);
}
void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
struct drm_syncobj_cb *cb)
{
- spin_lock(&syncobj->lock);
+ mutex_lock(&syncobj->cb_mutex);
list_del_init(&cb->node);
- spin_unlock(&syncobj->lock);
+ mutex_unlock(&syncobj->cb_mutex);
}
static void drm_syncobj_init(struct drm_syncobj *syncobj)
{
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
syncobj->timeline_context = dma_fence_context_alloc(1);
syncobj->timeline = 0;
syncobj->signal_point = 0;
init_waitqueue_head(&syncobj->wq);
INIT_LIST_HEAD(&syncobj->signal_pt_list);
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
static void drm_syncobj_fini(struct drm_syncobj *syncobj)
{
struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
list_for_each_entry_safe(signal_pt, tmp,
&syncobj->signal_pt_list, list) {
list_del(&signal_pt->list);
dma_fence_put(&signal_pt->fence_array->base);
kfree(signal_pt);
}
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
static struct dma_fence
@@ -249,14 +252,14 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
fences[num_fences++] = dma_fence_get(fence);
/* timeline syncobj must take this dependency */
if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
if (!list_empty(&syncobj->signal_pt_list)) {
tail_pt = list_last_entry(&syncobj->signal_pt_list,
struct drm_syncobj_signal_pt, list);
fences[num_fences++] =
dma_fence_get(&tail_pt->fence_array->base);
}
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
signal_pt->fence_array = dma_fence_array_create(num_fences, fences,
syncobj->timeline_context,
@@ -266,16 +269,16 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
goto fail;
}
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
if (syncobj->signal_point >= point) {
DRM_WARN("A later signal is ready!");
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
goto exist;
}
signal_pt->value = point;
list_add_tail(&signal_pt->list, &syncobj->signal_pt_list);
syncobj->signal_point = point;
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
wake_up_all(&syncobj->wq);
return 0;
@@ -294,7 +297,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj)
{
struct drm_syncobj_signal_pt *signal_pt, *tmp, *tail_pt;
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
tail_pt = list_last_entry(&syncobj->signal_pt_list,
struct drm_syncobj_signal_pt,
list);
@@ -315,7 +318,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj)
}
}
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
/**
* drm_syncobj_replace_fence - replace fence in a sync object.
@@ -344,13 +347,14 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
drm_syncobj_create_signal_pt(syncobj, fence, pt_value);
if (fence) {
struct drm_syncobj_cb *cur, *tmp;
+ LIST_HEAD(cb_list);
- spin_lock(&syncobj->lock);
+ mutex_lock(&syncobj->cb_mutex);
list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {
list_del_init(&cur->node);
cur->func(syncobj, cur);
}
- spin_unlock(&syncobj->lock);
+ mutex_unlock(&syncobj->cb_mutex);
}
}
EXPORT_SYMBOL(drm_syncobj_replace_fence);
@@ -386,11 +390,11 @@ drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags,
if (ret < 0)
return ret;
}
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
*fence = drm_syncobj_find_signal_pt_for_point(syncobj, point);
if (!*fence)
ret = -EINVAL;
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
return ret;
}
@@ -500,7 +504,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
kref_init(&syncobj->refcount);
INIT_LIST_HEAD(&syncobj->cb_list);
- spin_lock_init(&syncobj->lock);
+ spin_lock_init(&syncobj->pt_lock);
+ mutex_init(&syncobj->cb_mutex);
if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE)
syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
else
diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
index 5e8c5c027e09..29244cbcd05e 100644
--- a/include/drm/drm_syncobj.h
+++ b/include/drm/drm_syncobj.h
@@ -75,9 +75,13 @@ struct drm_syncobj {
*/
struct list_head cb_list;
/**
- * @lock: Protects syncobj list and write-locks &fence.
+ * @pt_lock: Protects pt list.
*/
- spinlock_t lock;
+ spinlock_t pt_lock;
+ /**
+ * @cb_mutex: Protects syncobj cb list.
+ */
+ struct mutex cb_mutex;
/**
* @file: A file backing for this syncobj.
*/
--
2.17.1
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