From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Date: Fri, 2 Aug 2013 16:55:21 +0000 (-0300)
Subject: upstream: [media] media: vb2: Take queue or device lock in mmap-related vb2 ioctl... 
X-Git-Tag: submit/tizen/20141121.110247~1996
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f881d610391ad2d4b360b6f4ee36e5703394e283;p=platform%2Fkernel%2Flinux-3.10.git

upstream: [media] media: vb2: Take queue or device lock in mmap-related vb2 ioctl handlers

The vb2_fop_mmap() and vb2_fop_get_unmapped_area() functions are plug-in
implementation of the mmap() and get_unmapped_area() file operations
that calls vb2_mmap() and vb2_get_unmapped_area() on the queue
associated with the video device. Neither the
vb2_fop_mmap/vb2_fop_get_unmapped_area nor the
v4l2_mmap/vb2_get_unmapped_area functions in the V4L2 core take any
lock, leading to race conditions between mmap/get_unmapped_area and
other buffer-related ioctls such as VIDIOC_REQBUFS.
Fix it by taking the queue or device lock around the vb2_mmap() and
vb2_get_unmapped_area() calls.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 8c91ae8..9f3cb61 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -2589,8 +2589,15 @@ EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct video_device *vdev = video_devdata(file);
+	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
+	int err;
 
-	return vb2_mmap(vdev->queue, vma);
+	if (lock && mutex_lock_interruptible(lock))
+		return -ERESTARTSYS;
+	err = vb2_mmap(vdev->queue, vma);
+	if (lock)
+		mutex_unlock(lock);
+	return err;
 }
 EXPORT_SYMBOL_GPL(vb2_fop_mmap);
 
@@ -2696,8 +2703,15 @@ unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
 		unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct video_device *vdev = video_devdata(file);
+	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
+	int ret;
 
-	return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);
+	if (lock && mutex_lock_interruptible(lock))
+		return -ERESTARTSYS;
+	ret = vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);
+	if (lock)
+		mutex_unlock(lock);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);
 #endif