From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: BUG: Mellanox crash with iommu=soft and swiotlb=force Date: Mon, 28 Sep 2015 23:04:50 +0200 Message-ID: <20150928210450.GA7610@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, konrad.wilk@oracle.com To: amirv@mellanox.com, idos@mellanox.com, netdev@vger.kernel.org Return-path: Received: from mail-la0-f54.google.com ([209.85.215.54]:34924 "EHLO mail-la0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751998AbbI1VEv (ORCPT ); Mon, 28 Sep 2015 17:04:51 -0400 Received: by laer8 with SMTP id r8so45798292lae.2 for ; Mon, 28 Sep 2015 14:04:49 -0700 (PDT) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Hi, In doing some performance experiments I found that using a 10G Mellanox MX354A Dual port FDR CX3 device on a server running Apache and running ab against that server causes the system to crash with 'iommu=soft swiotlb=force'. The same behavior is seen without these options on Dom0 running under Xen. I have tried this on v4.0 and v4.3-rc3. Examples of crashes: http://pastebin.ubuntu.com/11953498/ http://pastebin.ubuntu.com/11953443/ Kernel config (v4.3): http://paste.ubuntu.com/12605446/ To reproduce, host a file in apache server on a system with the Mellanox NIC (I used the 41K index file of the GCC manual) and run ab (apache bench) from a client machine, something like this: $ ab -n 100000 -c 100 http://10.10.1.2/gcc/index.html I'm afraid debugging this is out of my area of expertise. Is this something you could have a look at? Thanks, -Christoffer