From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Jason@zx2c4.com Received: from krantz.zx2c4.com (localhost [127.0.0.1]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 61d53fc4 for ; Tue, 29 May 2018 12:36:46 +0000 (UTC) Received: from frisell.zx2c4.com (frisell.zx2c4.com [192.95.5.64]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 86c1feac for ; Tue, 29 May 2018 12:36:46 +0000 (UTC) Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 7aecc57c for ; Tue, 29 May 2018 12:35:32 +0000 (UTC) Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 08e11921 (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128:NO) for ; Tue, 29 May 2018 12:35:31 +0000 (UTC) Received: by mail-oi0-f52.google.com with SMTP id b130-v6so12843519oif.12 for ; Tue, 29 May 2018 05:38:43 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: "Jason A. Donenfeld" Date: Tue, 29 May 2018 14:38:42 +0200 Message-ID: Subject: Re: Wireguard & hw flow offload incompatibility To: Felix Fietkau Content-Type: text/plain; charset="UTF-8" Cc: Jaap Buurman , openwrt-devel@lists.openwrt.org, WireGuard mailing list List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hey Felix, Per the below thread, I've been digging around trying to see what's going on. Apparently packets are hitting a virtual network interface's ndo_start_xmit with no dst when hardware offloading enabled. I assume that the path is something along the lines of a packet coming in on one of these hardware accelerated NICs and then being forwarded to the wireguard interface, which expects the dst. I found your ndo_flow_offload patchset, and I suspect that might have something to do with this. Any insights on dsts disappearing in skbs? Thanks, Jason On Tue, May 29, 2018 at 2:14 PM, Jason A. Donenfeld wrote= : > Hi Jaap, > > Thanks for the clarification. I downloaded the binary for that > hardware and triaged where the bug occurs [1]. This patch [2] should > probably fix it, but I'm rather surprised to see situations in which a > skb is missing a dst entry in ndo_start_xmit; this might point to > deeper kernel bugs in this hardware offloading feature, or some > alternative mechanism for routing being used when hardware offloading > is on. So I'm hesitant to merge this just yet, because perhaps this is > better handled in the compat layer, if it is in fact vendor silliness. > Do you have a link to the kernel source of these boxes? I'd like to > see what exactly the vendor is doing. And if you could try [2] and see > if that still crashes, this would be most appreciated. > > Thanks, > Jason > > [1] https://data.zx2c4.com/openwrt-mips-offloading-bug.png > [2] https://=D7=90.cc/Am4tZ0n8 > > On Tue, May 29, 2018 at 1:59 PM, Jaap Buurman wro= te: >> Dear Jason, >> >> This isn't a regression. This is simply the first time this has been >> observed. (hw) flow offload is a new feature, and hence this >> interaction with wireguard is also new. >> >> Yours sincerely, >> >> Jaap >> >> On Tue, May 29, 2018 at 1:54 PM, Jason A. Donenfeld wr= ote: >>> Hi Jaap, >>> >>> Thanks for the report. Is this a _new_ bug in _new_ version of >>> WireGuard that wasn't there before. Or is this the first time you've >>> observed this? >>> >>> Thanks, >>> Jason > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Original Mail =3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D > >> Dear all, >> >> When running a wireguard interface on the latest Lede master branch, >> the router will crash as soon as traffic hits the wireguard interface >> while (hw) flow offloading is enabled. I am not sure whether this is a >> bug with wireguard, hw flow offload, both or neither, so I am >> reporting the bug to both mailinglists. A more detailed description >> plus a properly formatted stack trace can be found on Lede's bug >> tracker: https://bugs.openwrt.org/index.php?do=3Ddetails&task_id=3D1539 >> >> If you require any additional information, please do not hesitate to >> contact me. Thank you very much in advance. >> >> Yours sincerely, >> >> Jaap Buurman