Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752857Ab2K1III (ORCPT ); Wed, 28 Nov 2012 03:08:08 -0500 Received: from shrek-wifi.podlesie.net ([93.179.225.50]:49898 "EHLO shrek.podlesie.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752630Ab2K1IIH (ORCPT ); Wed, 28 Nov 2012 03:08:07 -0500 Date: Wed, 28 Nov 2012 09:08:04 +0100 From: Krzysztof Mazur To: David Woodhouse Cc: chas williams - CONTRACTOR , davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, nathan@traverse.com.au Subject: Re: [PATCH] br2684: don't send frames on not-ready vcc Message-ID: <20121128080804.GA23175@shrek.podlesie.net> References: <1350926091-12642-1-git-send-email-krzysiek@podlesie.net> <1350926091-12642-3-git-send-email-krzysiek@podlesie.net> <1354036592.2534.6.camel@shinybook.infradead.org> <20121127173906.GA11390@shrek.podlesie.net> <1354039349.2534.11.camel@shinybook.infradead.org> <20121127135434.0728cd4f@thirdoffive.cmf.nrl.navy.mil> <1354055783.2534.18.camel@shinybook.infradead.org> <1354058916.2534.25.camel@shinybook.infradead.org> <20121127235129.GA20080@shrek.podlesie.net> <1354064086.21562.10.camel@shinybook.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1354064086.21562.10.camel@shinybook.infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2575 Lines: 73 On Wed, Nov 28, 2012 at 12:54:46AM +0000, David Woodhouse wrote: > On Wed, 2012-11-28 at 00:51 +0100, Krzysztof Mazur wrote: > > If you do this actually it's better to don't use patch 1/7 because > > it introduces race condition that you found earlier. > > Right. I've omitted that from the git tree I just pushed out. > > > With this patch you have still theoretical race that was fixed in patches > > 5 and 8 in pppoatm series, but I never seen that in practice. > > And I think it's even less likely for br2684. At least with pppoatm you > might have had pppd sending frames. But for br2684 they *only* come from > its start_xmit function... which is serialised anyway. > > I do get strange oopses when I try to add BQL to br2684, but that's not > something to be looking at at 1am... > > I *do* need the equivalent of your patch 4, which is the module_put > race. > I think you might need also an equivalent of "[PATCH v3 3/7] pppoatm: allow assign only on a connected socket". I'm not sure yet. In will test if I can trigger that Oops on pppoatm without that patch. Testing vcc flags might be sufficient - that's what I did in the first patch, but you asked what about SOCK_CONNECTED, and I think it was really needed. Krzysiek -- >8 -- Subject: [PATCH] br2684: allow assign only on a connected socket The br2684 does not check if used vcc is in connected state, causing potential Oops in pppoatm_send() when vcc->send() is called on not fully connected socket. Now br2684 can be assigned only on connected sockets; otherwise -EINVAL error is returned. Signed-off-by: Krzysztof Mazur --- net/atm/br2684.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/atm/br2684.c b/net/atm/br2684.c index 59e8edb..e88998c 100644 --- a/net/atm/br2684.c +++ b/net/atm/br2684.c @@ -704,10 +704,13 @@ static int br2684_ioctl(struct socket *sock, unsigned int cmd, return -ENOIOCTLCMD; if (!capable(CAP_NET_ADMIN)) return -EPERM; - if (cmd == ATM_SETBACKEND) + if (cmd == ATM_SETBACKEND) { + if (sock->state != SS_CONNECTED) + return -EINVAL; return br2684_regvcc(atmvcc, argp); - else + } else { return br2684_create(argp); + } #ifdef CONFIG_ATM_BR2684_IPFILTER case BR2684_SETFILT: if (atmvcc->push != br2684_push) -- 1.8.0.411.g71a7da8 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/