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Commit 12561ad6 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] videobuf2-core: take mmap_sem before calling __qbuf_userptr 



(Changes since v2: dropped local variable as suggested by Laurent)

Commit f035eb4e (videobuf2: fix lockdep warning)
unfortunately removed the mmap_sem lock that is needed around the call to
__qbuf_userptr. Amazingly nobody noticed this (especially me as the author)
until Jan Kara pointed this out to me.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Reported-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 825fd08d

drivers/media/v4l2-core/videobuf2-core.c

+2 −0
Original line number Diff line number Diff line
@@ -1627,7 +1627,9 @@ 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(&current->mm->mmap_sem);

		ret = __qbuf_userptr(vb, b);

		up_read(&current->mm->mmap_sem);

		break;

	case V4L2_MEMORY_DMABUF:

		ret = __qbuf_dmabuf(vb, b);