Commit f035eb4e976ef5a059e30bc91cfd310ff030a7d3 (videobuf2: fix lockdep warning)
unfortunately removed the mmap_sem lock that is needed around the call to
__qbuf_userptr. Amazingly nobody noticed this until Jan Kara pointed this out
to me.
Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
Reported-by: Jan Kara <j...@suse.cz>
---
drivers/media/v4l2-core/videobuf2-core.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c
b/drivers/media/v4l2-core/videobuf2-core.c
index 5b808e2..2f6ac7e 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1591,6 +1591,7 @@ static void __enqueue_in_driver(struct vb2_buffer *vb)
static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
struct vb2_queue *q = vb->vb2_queue;
+ struct rw_semaphore *mmap_sem;
int ret;
ret = __verify_length(vb, b);
@@ -1627,7 +1628,9 @@ static int __buf_prepare(struct vb2_buffer *vb, const
struct v4l2_buffer *b)
ret = __qbuf_mmap(vb, b);
break;
case V4L2_MEMORY_USERPTR:
+ down_read(mmap_sem);
ret = __qbuf_userptr(vb, b);
+ up_read(mmap_sem);
break;
case V4L2_MEMORY_DMABUF:
ret = __qbuf_dmabuf(vb, b);
--
2.0.1
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