linux-kernel - [PATCH] drm/virtio: Don't return invalid caps on timeout

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Message-Id: <20171127142126.25765-1-tomeu.vizoso@collabora.com>
Date:   Mon, 27 Nov 2017 15:21:25 +0100
From:   Tomeu Vizoso <tomeu.vizoso@...labora.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        David Airlie <airlied@...ux.ie>,
        Gerd Hoffmann <kraxel@...hat.com>,
        virtualization@...ts.linux-foundation.org (open list:VIRTIO GPU DRIVER),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] drm/virtio: Don't return invalid caps on timeout

If the wait timeouts, the caps are probably invalid and we shouldn't be
passing them to userspace.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index b94bd5440e57..902120ad4a6d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -517,6 +517,8 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev,
 
 	ret = wait_event_timeout(vgdev->resp_wq,
 				 atomic_read(&cache_ent->is_valid), 5 * HZ);
+	if (!ret)
+		return -EBUSY;
 
 	ptr = cache_ent->caps_cache;
 
-- 
2.14.3