Patch "[media] vb2-memops: Fix over allocation of frame vectors" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

[media] vb2-memops: Fix over allocation of frame vectors

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
vb2-memops-fix-over-allocation-of-frame-vectors.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ricardo Ribalda <[email protected]>
Date: Thu, 3 Mar 2016 16:12:48 -0300
Subject: [media] vb2-memops: Fix over allocation of frame vectors

From: Ricardo Ribalda Delgado <[email protected]>

commit 89a095668304e8a02502ffd35edacffdbf49aa8c upstream.

On page unaligned frames, create_framevec forces get_vaddr_frames to allocate an extra page at the end of the buffer. Under some circumstances, this leads to -EINVAL on VIDIOC_QBUF.

E.g:
We have vm_a that vm_area that goes from 0x1000 to 0x3000. And a frame that goes from 0x1800 to 0x2800, i.e. 2 pages.

frame_vector_create will be called with the following params:

get_vaddr_frames(0x1800, 2, write, 1, vec);

get_vaddr will allocate the first page after checking that the memory 0x1800-0x27ff is valid, but it will not allocate the second page because the range 0x2800-0x37ff is out of the vm_a range. This results in create_framevec returning -EFAULT

Error Trace:

[ 9083.793015] video0: VIDIOC_QBUF: 00:00:00.00000000 index=1,
type=vid-cap, flags=0x00002002, field=any, sequence=0,
memory=userptr, bytesused=0, offset/userptr=0x7ff2b023ca80, length=5765760
[ 9083.793028] timecode=00:00:00 type=0, flags=0x00000000,
frames=0, userbits=0x00000000
[ 9083.793117] video0: VIDIOC_QBUF: error -22: 00:00:00.00000000

index=2, type=vid-cap, flags=0x00000000, field=any, sequence=0, memory=userptr, bytesused=0, offset/userptr=0x7ff2b07bc500, length=5765760

Also use true instead of 1 since that argument is a bool in the get_vaddr_frames() prototype.

---
 drivers/media/v4l2-core/videobuf2-memops.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -49,7 +49,7 @@ struct frame_vector *vb2_create_framevec
 	vec = frame_vector_create(nr);
 	if (!vec)
 		return ERR_PTR(-ENOMEM);
-	ret = get_vaddr_frames(start, nr, write, 1, vec);
+	ret = get_vaddr_frames(start & PAGE_MASK, nr, write, true, vec);
 	if (ret < 0)
 		goto out_destroy;
 	/* We accept only complete set of PFNs */

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/vb2-memops-fix-over-allocation-of-frame-vectors.patch queue-4.5/media-vb2-fix-regression-on-poll-for-rw-mode.patch