Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752706AbdI1Kdo (ORCPT ); Thu, 28 Sep 2017 06:33:44 -0400 Received: from orcrist.hmeau.com ([104.223.48.154]:47576 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbdI1Kdm (ORCPT ); Thu, 28 Sep 2017 06:33:42 -0400 Date: Thu, 28 Sep 2017 18:33:12 +0800 From: Herbert Xu To: Casey Leedom Cc: "Raj, Ashok" , Robin Murphy , Dan Williams , Harsh Jain , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-crypto@vger.kernel.org" , "dwmw2@infradead.org" , Michael Werner , "nd@arm.com" Subject: Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU Message-ID: <20170928103312.GB8118@gondor.apana.org.au> References: <6d2af675-7b97-6eaf-4daa-d7bf80a05923@chelsio.com> <437a9bd8-d4d6-22ca-1a64-1a3e73f1101a@arm.com> <20170927181802.3dcd7efb@m750.lan> <20170927144847.GA95654@otc-nc-03> <20170927190745.GA96373@otc-nc-03> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1807 Lines: 45 On Wed, Sep 27, 2017 at 10:13:04PM +0000, Casey Leedom wrote: > | From: Raj, Ashok > | Sent: Wednesday, September 27, 2017 12:07 PM > | > | looking at the debug output i got from Harsh it still looks like a bug in > | the code. > | > | [ 538.284589] __domain_mapping nr_pages 0x1 > | [ 538.284600] __domain_mapping sg_res 0x1 sg->dma_address 0xf291000e dma len > | 0x38 pteval 0x3cbce3003 phys_pfn 0x3cbce3 > | [ 538.284604] chelsio driver - offset 4110 len 56 dma addr f291000e dma len > | 56 > | [ 538.284667] DMAR: DRHD: handling fault status reg 2 > | [ 538.290017] DMAR: [DMA Write] Request device [02:00.4] fault addr f2910000 > | [fault reason 05] PTE Write access is not set > | > | somehow when crypto_authenc_encrypt() -> scatterwalk_ffwd()-> sg_set_page() > | > | ->sg_set_page(dst, sg_page(src), src->length - len, src->offset + len); > | > | src->offset + len gets set as sg->offset in sg_set_page(). Either the > | assumption that there should be room is incorrect, or some higher order > | crypto > | code that ends up setting the offset did the wrong calculation. > | > | if src->offset is already towards the end of the page, then offset+len will > | go beyond the end of page. > > Hhmmm, it seems like we need Herbert to comment on this. > > Herbert, is there any specific debugging information that you'd like to > see here? OK I was mistaken. While SG lists can contain entries that are larger than PAGE_SIZE, there is no reason why scatterwalk_ffwd should gratuitously insert a page_offset that is greater than PAGE_SIZE. Harsh, can you please submit your original patch with a sign-off? Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt