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* [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock
@ 2018-10-26  6:20 Chunming Zhou
  2018-10-26  6:55 ` ✓ Fi.CI.BAT: success for drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock (rev2) Patchwork
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Chunming Zhou @ 2018-10-26  6:20 UTC (permalink / raw)
  To: dri-devel; +Cc: Chunming Zhou, intel-gfx, Christian König, Julia Lawall

drivers/gpu/drm/drm_syncobj.c:202:4-14: ERROR: function drm_syncobj_find_signal_pt_for_point called on line 390 inside lock on line 389 but uses GFP_KERNEL

  Find functions that refer to GFP_KERNEL but are called with locks held.

Generated by: scripts/coccinelle/locks/call_kern.cocci

v2:
syncobj->timeline still needs protect.

v3:
use a global signaled fence instead of re-allocation.

v4:
Don't need moving lock.
Don't expose func.

v5:
rename func and directly return.

Tested by: syncobj_wait and ./deqp-vk -n dEQP-VK.*semaphore* with
lock debug kernel options enabled.

Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Christian König <easy2remember.chk@googlemail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
CC: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_syncobj.c | 36 ++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index b7eaa603f368..d1c6f21c72b5 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -80,6 +80,23 @@ struct drm_syncobj_signal_pt {
 	struct list_head list;
 };
 
+static DEFINE_SPINLOCK(signaled_fence_lock);
+static struct dma_fence signaled_fence;
+
+static struct dma_fence *drm_syncobj_get_stub_fence(void)
+{
+	spin_lock(&signaled_fence_lock);
+	if (!signaled_fence.ops) {
+		dma_fence_init(&signaled_fence,
+			       &drm_syncobj_stub_fence_ops,
+			       &signaled_fence_lock,
+			       0, 0);
+		dma_fence_signal_locked(&signaled_fence);
+	}
+	spin_unlock(&signaled_fence_lock);
+
+	return dma_fence_get(&signaled_fence);
+}
 /**
  * drm_syncobj_find - lookup and reference a sync object.
  * @file_private: drm file private pointer
@@ -113,23 +130,8 @@ static struct dma_fence
 	struct drm_syncobj_signal_pt *signal_pt;
 
 	if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) &&
-	    (point <= syncobj->timeline)) {
-		struct drm_syncobj_stub_fence *fence =
-			kzalloc(sizeof(struct drm_syncobj_stub_fence),
-				GFP_KERNEL);
-
-		if (!fence)
-			return NULL;
-		spin_lock_init(&fence->lock);
-		dma_fence_init(&fence->base,
-			       &drm_syncobj_stub_fence_ops,
-			       &fence->lock,
-			       syncobj->timeline_context,
-			       point);
-
-		dma_fence_signal(&fence->base);
-		return &fence->base;
-	}
+	    (point <= syncobj->timeline))
+		return drm_syncobj_get_stub_fence();
 
 	list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) {
 		if (point > signal_pt->value)
-- 
2.17.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock
@ 2018-10-25 15:08 Chunming Zhou
  2018-10-25 16:31 ` Chris Wilson
  2018-10-25 18:58 ` Christian König
  0 siblings, 2 replies; 10+ messages in thread
From: Chunming Zhou @ 2018-10-25 15:08 UTC (permalink / raw)
  To: dri-devel; +Cc: intel-gfx, Christian König, Julia Lawall

drivers/gpu/drm/drm_syncobj.c:202:4-14: ERROR: function drm_syncobj_find_signal_pt_for_point called on line 390 inside lock on line 389 but uses GFP_KERNEL

  Find functions that refer to GFP_KERNEL but are called with locks held.

Generated by: scripts/coccinelle/locks/call_kern.cocci

v2:
syncobj->timeline still needs protect.

v3:
use a global signaled fence instead of re-allocation.

v4:
Don't need moving lock.
Don't expose func.

Tested by: syncobj_wait and ./deqp-vk -n dEQP-VK.*semaphore* with
lock debug kernel options enabled.

Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Christian König <easy2remember.chk@googlemail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
CC: Julia Lawall <julia.lawall@lip6.fr>
---
 drivers/gpu/drm/drm_syncobj.c | 41 ++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index b7eaa603f368..fab0a2cf672e 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -80,6 +80,23 @@ struct drm_syncobj_signal_pt {
 	struct list_head list;
 };
 
+static DEFINE_SPINLOCK(signaled_fence_lock);
+static struct dma_fence signaled_fence;
+
+static struct dma_fence *drm_syncobj_signaled_fence_get(void)
+{
+	spin_lock(&signaled_fence_lock);
+	if (!signaled_fence.ops) {
+		dma_fence_init(&signaled_fence,
+			       &drm_syncobj_stub_fence_ops,
+			       &signaled_fence_lock,
+			       0, 0);
+		dma_fence_signal_locked(&signaled_fence);
+	}
+	spin_unlock(&signaled_fence_lock);
+
+	return dma_fence_get(&signaled_fence);
+}
 /**
  * drm_syncobj_find - lookup and reference a sync object.
  * @file_private: drm file private pointer
@@ -111,24 +128,12 @@ static struct dma_fence
 				      uint64_t point)
 {
 	struct drm_syncobj_signal_pt *signal_pt;
+	struct dma_fence *f = NULL;
 
 	if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) &&
 	    (point <= syncobj->timeline)) {
-		struct drm_syncobj_stub_fence *fence =
-			kzalloc(sizeof(struct drm_syncobj_stub_fence),
-				GFP_KERNEL);
-
-		if (!fence)
-			return NULL;
-		spin_lock_init(&fence->lock);
-		dma_fence_init(&fence->base,
-			       &drm_syncobj_stub_fence_ops,
-			       &fence->lock,
-			       syncobj->timeline_context,
-			       point);
-
-		dma_fence_signal(&fence->base);
-		return &fence->base;
+		f = drm_syncobj_signaled_fence_get();
+		goto out;
 	}
 
 	list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) {
@@ -137,9 +142,11 @@ static struct dma_fence
 		if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) &&
 		    (point != signal_pt->value))
 			continue;
-		return dma_fence_get(&signal_pt->fence_array->base);
+		f = dma_fence_get(&signal_pt->fence_array->base);
+		goto out;
 	}
-	return NULL;
+out:
+	return f;
 }
 
 static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
-- 
2.17.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2018-10-26 13:08 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-26  6:20 [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock Chunming Zhou
2018-10-26  6:55 ` ✓ Fi.CI.BAT: success for drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock (rev2) Patchwork
2018-10-26  7:43 ` [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock Christian König
2018-10-26  8:28   ` zhoucm1
2018-10-26 12:13     ` Koenig, Christian
2018-10-26 11:49 ` Maarten Lankhorst
2018-10-26 13:08 ` ✓ Fi.CI.IGT: success for drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock (rev2) Patchwork
  -- strict thread matches above, loose matches on Subject: below --
2018-10-25 15:08 [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock Chunming Zhou
2018-10-25 16:31 ` Chris Wilson
2018-10-25 18:58 ` Christian König

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