From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislaw Gruszka Subject: Re: [GIT] Networking Date: Mon, 7 Nov 2011 12:40:55 +0100 Message-ID: <20111107114054.GA2395@redhat.com> References: <20111025.063206.2273357152859701628.davem@davemloft.net> <1320426222.3969.121.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , David Miller , "Grumbach, Emmanuel" , "Guy, Wey-Yi W" , "John W. Linville" , "akpm@linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: Johannes Berg Return-path: Content-Disposition: inline In-Reply-To: <1320426222.3969.121.camel@jlt3.sipsolutions.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, Nov 04, 2011 at 06:03:42PM +0100, Johannes Berg wrote: > On Tue, 2011-10-25 at 12:26 +0000, Linus Torvalds wrote: > > On Tue, Oct 25, 2011 at 12:32 PM, David Miller wrote: > > > > > > The most visible thing in here is the reorganization of the drivers > > > under drivers/net. > > > > Nope, the most visible thing are some new annoying warnings, that seem > > absolutely broken. > > > > At the very minimum, that WARN_ON(1) should be a WARN_ON_ONCE() or > > something like that. Because showing it over an dover again is not > > helpful. > > > > Added the people who signed off on the changes to the affected files, > > since they hopefully know why this happens and can fix it.. > > Sorry for the late reply. > > I think this was actually caused by some changes from Ben Greear > "optimising" stuff in net/mac80211/work.c and keeping the wrong channel, > Stanislaw was also looking at this at some point I think. I agree that > it would be good to change to WARN_ON_ONCE(), will do that. > > The warning itself has been around forever, but the fact that it > triggers now is probably related to the channel work & band switches. I think this problem is related with linuxcon :-) and it is not current regression, i.e. Ben's off-channel code was already committed in 3.0. I have also RHEL6 - 2.6.32 bug report about that: https://bugzilla.redhat.com/show_bug.cgi?id=749125 Probably there was something special on linuxcon wireless network (i.e. big contention) what cause people start to see this warning. Eventually nobody use wireless except conferences :-/ I have one pending patch which fix other instance of the warning (started at ieee80211_tx_status()). I'll post it today. As Ben mentioned, two fixes are pending in wireless-testing tree: http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=commitdiff;h=682ba5a44516529b29fc780c055e06104d36e31e http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=commitdiff;h=776308dd5fa8a41e8bbb79818a66bd68a7db757e However, I'm not sure if that cover all possible situations when warning can be triggered. We need to do a careful review of channel switching in mac80211. Stanislaw