From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kernel.org ([198.145.29.99]:43760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752461AbeBENvJ (ORCPT ); Mon, 5 Feb 2018 08:51:09 -0500 Date: Mon, 5 Feb 2018 22:51:05 +0900 From: Masami Hiramatsu To: Marek Szyprowski Cc: Pawel Osciak , Kyungmin Park , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, orito.takao@socionext.com, Fumihiro ATSUMI Subject: Re: [PATCH] [BUGFIX] media: vb2: Fix videobuf2 to map correct area Message-Id: <20180205225105.6eb3a8e5ed93c87bf6cfd14e@kernel.org> In-Reply-To: <2af9a288-86e8-100a-4459-bc913f3cb99d@samsung.com> References: <151779784111.20697.5012233804870630070.stgit@devbox> <2af9a288-86e8-100a-4459-bc913f3cb99d@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On Mon, 05 Feb 2018 09:47:46 +0100 Marek Szyprowski wrote: > Hi Masami, > > On 2018-02-05 03:30, Masami Hiramatsu wrote: > > Fixes vb2_vmalloc_get_userptr() to ioremap correct area. > > Since the current code does ioremap the page address, if the offset > 0, > > it does not do ioremap the last page and results in kernel panic. > > > > This fixes to pass the page address + offset to ioremap so that ioremap > > can map correct area. Also, this uses __pfn_to_phys() to get the physical > > address of given PFN. > > > > Signed-off-by: Masami Hiramatsu > > Reported-by: Takao Orito > > --- > > drivers/media/v4l2-core/videobuf2-vmalloc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c > > index 3a7c80cd1a17..896f2f378b40 100644 > > --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c > > +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c > > @@ -106,7 +106,7 @@ static void *vb2_vmalloc_get_userptr(struct device *dev, unsigned long vaddr, > > if (nums[i-1] + 1 != nums[i]) > > goto fail_map; > > buf->vaddr = (__force void *) > > - ioremap_nocache(nums[0] << PAGE_SHIFT, size); > > + ioremap_nocache(__pfn_to_phys(nums[0]) + offset, size); > > Thanks for reporting this issue. However the above line doesn't look like > a proper fix. Please note that at the end of that function there is already > "buf->vaddr += offset;". I see. > > IMHO the proper fix is to create a larger mapping, which would include the > in-page start offset: > > ioremap_nocache(__pfn_to_phys(nums[0]), offset + size); Yes, sorry it's my mistake. I misunderstood ioremap_nocache(addr, size) remaps the PAGE of addr to PAGE of (addr+size). Yours is correct. Thank you, > BTW, thanks for updating "<< PAGE_SHIFT" to better __pfn_to_phys() macro! > > > } else { > > buf->vaddr = vm_map_ram(frame_vector_pages(vec), n_pages, -1, > > PAGE_KERNEL); > > > > > > > > > > Best regards > -- > Marek Szyprowski, PhD > Samsung R&D Institute Poland > -- Masami Hiramatsu