From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Clayton Subject: Re: Possible networking regression in 3.6.0 Date: Tue, 18 Sep 2012 15:31:56 +0100 Message-ID: <505885DC.1060006@googlemail.com> References: <5057455A.7050108@googlemail.com> <50588371.40103@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mail-ey0-f174.google.com ([209.85.215.174]:49538 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933149Ab2IRObs (ORCPT ); Tue, 18 Sep 2012 10:31:48 -0400 Received: by eaac11 with SMTP id c11so2865642eaa.19 for ; Tue, 18 Sep 2012 07:31:47 -0700 (PDT) In-Reply-To: <50588371.40103@googlemail.com> Sender: netdev-owner@vger.kernel.org List-ID: >> ... >> r8169 47159 0 >> >> From the host I can successfully ping the guest, tap0 and the router as >> you would expect, but from the guest, although I can ping the host and >> tap0, I cannot ping the router. In practice, this means I have no >> internet access from the guest. As I say, this configuration works >> perfectly under 3.5.x and 3.4.x kernels. >> >> I'll do a coarse-grained "bisect" of Linus' 3.6 release candidates and >> report back, but does anyone have any prime-suspect patches that may be >> at the cause of this problem? >> > > -rc1 turned out to have the problem so I've bisected between 3.5 and > 3.6-rc1. I arrived at: > > $ git bisect bad > d2d68ba9fe8b38eb03124b3176a013bb8aa2b5e5 is the first bad commit > commit d2d68ba9fe8b38eb03124b3176a013bb8aa2b5e5 > Author: David S. Miller > Date: Tue Jul 17 12:58:50 2012 -0700 > > ipv4: Cache input routes in fib_info nexthops. > > Caching input routes is slightly simpler than output routes, since we > don't need to be concerned with nexthop exceptions. (locally > destined, and routed packets, never trigger PMTU events or redirects > that will be processed by us). > > However, we have to elide caching for the DIRECTSRC and non-zero itag > cases. > > Signed-off-by: David S. Miller > > :040000 040000 6bbc75c1cbe62bf84ea412d3b98adf2b614779cd > 3ad7256b4a71e63ca4530977c0550121ea803d35 M include > :040000 040000 18c2a950a53c4eec9bfa12185d1e382dfed74af8 > a2ab6157d6cd54930da395758c6ded3a225d1f04 M net > > The bisect log: > git bisect start > # bad: [0d7614f09c1ebdbaa1599a5aba7593f147bf96ee] Linux 3.6-rc1 > git bisect bad 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee > # good: [28a33cbc24e4256c143dce96c7d93bf423229f92] Linux 3.5 > git bisect good 28a33cbc24e4256c143dce96c7d93bf423229f92 > # bad: [614a6d4341b3760ca98a1c2c09141b71db5d1e90] Merge branch 'for-3.6' > of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup > git bisect bad 614a6d4341b3760ca98a1c2c09141b71db5d1e90 > # bad: [320f5ea0cedc08ef65d67e056bcb9d181386ef2c] genetlink: define > lockdep_genl_is_held() when CONFIG_LOCKDEP > git bisect bad 320f5ea0cedc08ef65d67e056bcb9d181386ef2c > # good: [0cd06647b7c24f6633e32a505930a9aa70138c22] Merge branch 'master' > of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next > git bisect good 0cd06647b7c24f6633e32a505930a9aa70138c22 > # good: [dbfa600148a25903976910863c75dae185f8d187] cxgb3: set maximal > number of default RSS queues > git bisect good dbfa600148a25903976910863c75dae185f8d187 > # good: [efdfad3205403e1d1c5c0bdcbdb647ddd89bfaa3] bnx2: Try to recover > from PCI block reset > git bisect good efdfad3205403e1d1c5c0bdcbdb647ddd89bfaa3 > # good: [1bf91cdc1bba94ea062a9147d924815c13f029f2] ixgbe: Drop > references to deprecated pci_ DMA api and instead use dma_ API > git bisect good 1bf91cdc1bba94ea062a9147d924815c13f029f2 > # good: [b6dfd939fdc249fcf8cd7b8006f76239b33eb581] ixgbe: add support > for new 82599 device > git bisect good b6dfd939fdc249fcf8cd7b8006f76239b33eb581 > # good: [3ba97381343b271296487bf073eb670d5465a8b8] net: ethernet: > davinci_emac: add pm_runtime support > git bisect good 3ba97381343b271296487bf073eb670d5465a8b8 > # bad: [5e9965c15ba88319500284e590733f4a4629a288] Merge branch > 'kill_rtcache' > git bisect bad 5e9965c15ba88319500284e590733f4a4629a288 > # good: [f5b0a8743601a4477419171f5046bd07d1c080a0] net: Document > dst->obsolete better. > git bisect good f5b0a8743601a4477419171f5046bd07d1c080a0 > # bad: [ba3f7f04ef2b19aace38f855aedd17fe43035d50] ipv4: Kill > FLOWI_FLAG_RT_NOCACHE and associated code. > git bisect bad ba3f7f04ef2b19aace38f855aedd17fe43035d50 > # good: [f2bb4bedf35d5167a073dcdddf16543f351ef3ae] ipv4: Cache output > routes in fib_info nexthops. > git bisect good f2bb4bedf35d5167a073dcdddf16543f351ef3ae > # bad: [d2d68ba9fe8b38eb03124b3176a013bb8aa2b5e5] ipv4: Cache input > routes in fib_info nexthops. > git bisect bad d2d68ba9fe8b38eb03124b3176a013bb8aa2b5e5 > > Checking out the parent commit > (f2bb4bedf35d5167a073dcdddf16543f351ef3ae) and building and installing > the kernel gives a working configuration, so I'm pretty confident in the > outcome of the bisect. Reversing the patch gives errors, so I've not > tested master with the patch reversed. > > Let me know if I can help in any way to identify a fix. > Sorry, I forgot to say that I also have tried running TinyCore Linux as a KVM guest on a 3.6.0-rc6 kernel, and I can ping the router fine, so the problem seems to be something specifically related to ruuning Windows XP as the guest. I don't have any other guests installed so that's as much as I can say, although I could maybe install a Win7 guest tomorrow if that would help. > Chris > >> Let me know if there are any other diagnostics I can provide. Also, as >> I'm not subscribed to netdev, please cc me to any reply. >> >> Thanks, >> >> Chris