linux-kernel - [PATCH v5 12/12] drm/drm_ioctl.c: Break ioctl when drm device not registered

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Date:   Thu,  6 Apr 2017 20:31:25 +0800
From:   Jeffy Chen <jeffy.chen@...k-chips.com>
To:     linux-kernel@...r.kernel.org
Cc:     briannorris@...omium.org, dianders@...omium.org,
        tfiga@...omium.org, seanpaul@...omium.org, zyw@...k-chips.com,
        mark.yao@...k-chips.com, Jeffy Chen <jeffy.chen@...k-chips.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>
Subject: [PATCH v5 12/12] drm/drm_ioctl.c: Break ioctl when drm device not registered

After unbinding drm, the user space may still owns the drm dev fd,
and may still be able to call drm ioctl.

Add a sanity check here to prevent that from happening.

Signed-off-by: Jeffy Chen <jeffy.chen@...k-chips.com>
---

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None

 drivers/gpu/drm/drm_ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 7d6deaa..15beb11 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -674,7 +674,7 @@ long drm_ioctl(struct file *filp,
 
 	dev = file_priv->minor->dev;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_device_is_unplugged(dev) || !dev->registered)
 		return -ENODEV;
 
 	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
-- 
2.1.4