Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757192AbcCCTM6 (ORCPT ); Thu, 3 Mar 2016 14:12:58 -0500 Received: from mail-lb0-f169.google.com ([209.85.217.169]:34595 "EHLO mail-lb0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754943AbcCCTM4 (ORCPT ); Thu, 3 Mar 2016 14:12:56 -0500 From: Ricardo Ribalda Delgado To: albert@newtec.dk, Jan Kara , Pawel Osciak , Marek Szyprowski , Kyungmin Park , Hans Verkuil , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ricardo Ribalda Delgado Subject: [PATCH 1/2] [media] vb2-memops: Fix over allocation of frame vectors Date: Thu, 3 Mar 2016 20:12:48 +0100 Message-Id: <1457032369-10503-1-git-send-email-ricardo.ribalda@gmail.com> X-Mailer: git-send-email 2.7.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2261 Lines: 59 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 Fixes: 21fb0cb7ec65 ("[media] vb2: Provide helpers for mapping virtual addresses") Reported-by: Albert Antony Signed-off-by: Ricardo Ribalda Delgado --- Maybe we should cc stable. This error has not pop-out yet because userptr is usually called with memory on the heap and malloc usually overallocate. This error has been a pain to trace :). Regards! drivers/media/v4l2-core/videobuf2-memops.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/videobuf2-memops.c b/drivers/media/v4l2-core/videobuf2-memops.c index dbec5923fcf0..e4e4976c6849 100644 --- a/drivers/media/v4l2-core/videobuf2-memops.c +++ b/drivers/media/v4l2-core/videobuf2-memops.c @@ -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, 1, vec); if (ret < 0) goto out_destroy; /* We accept only complete set of PFNs */ -- 2.7.0