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

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.

Fixes: 21fb0cb7ec ("[media] vb2: Provide helpers for mapping virtual addresses")

Reported-by: Albert Antony <albert@newtec.dk>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
[hans.verkuil@cisco.com: merged the 'bool' change into this patch]
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>      # for v4.3 and up
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Ricardo Ribalda 2016-03-03 16:12:48 -03:00 committed by Mauro Carvalho Chehab
parent b93876845c
commit 89a0956683
1 changed files with 1 additions and 1 deletions
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2
drivers/media/v4l2-core/videobuf2-memops.c
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@ -49,7 +49,7 @@ struct frame_vector *vb2_create_framevec(unsigned long start,
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 */