On 28-09-2017 16:03, Herbert Xu wrote: > On Wed, Sep 27, 2017 at 10:13:04PM +0000, Casey Leedom wrote: >> | From: Raj, Ashok <ashok....@intel.com> >> | 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? Herbert, There are some points which bothers me. 1) That patch solve panic later on after reporting the issue, I can see DMA_write error traces with iperf traffic. 2) It seems we(crypto) are not the only one who adjust offsets like this. refer "__skb_to_sgvec <http://elixir.free-electrons.com/linux/latest/ident/__skb_to_sgvec>" . There can be many more.
sg_set_page <http://elixir.free-electrons.com/linux/latest/ident/sg_set_page>(&sg[elt], skb_frag_page <http://elixir.free-electrons.com/linux/latest/ident/skb_frag_page>(frag <http://elixir.free-electrons.com/linux/latest/ident/frag>), copy <http://elixir.free-electrons.com/linux/latest/ident/copy>, frag <http://elixir.free-electrons.com/linux/latest/ident/frag>->page_offset <http://elixir.free-electrons.com/linux/latest/ident/page_offset>+offset-start); 3) Yesterday Ashok suggested to run the test with boot parameter Intel_iommu=sp_off. With yhis Even Iperf traffic runs seemlessly. Don't know what this has changed. > > Thanks,
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