From 8a90f1a61c9b31bd0c89b8456fa4dce91ad69c57 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Fri, 2 Aug 2013 13:55:21 -0300 Subject: [PATCH] [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 Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-core.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 9fc4bab2da97..c9b50c7665de 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -2578,8 +2578,15 @@ 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); @@ -2685,8 +2692,15 @@ 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 -- GitLab