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Commit 4fb2c933 authored by Chunming Zhou's avatar Chunming Zhou Committed by Christian König
Browse files

drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock 



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: default avatarChunming 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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/258623/
parent b1ab1f32

drivers/gpu/drm/drm_syncobj.c

+19 −17
Original line number Diff line number Diff line
@@ -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)