From 4fb2c933c9656435e8300fd6011daa3d4b0128fd Mon Sep 17 00:00:00 2001 From: Chunming Zhou Date: Fri, 26 Oct 2018 14:20:27 +0800 Subject: [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Cc: Maarten Lankhorst Cc: intel-gfx@lists.freedesktop.org Cc: Christian König Cc: Chris Wilson CC: Julia Lawall Reviewed-by: Chris Wilson Reviewed-by: Christian König Reviewed-by: Maarten Lankhorst Signed-off-by: Christian König Link: https://patchwork.freedesktop.org/patch/258623/ --- 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 c8252cd4c02d..d3e2335b88f9 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) -- 2.11.0