Return-path: Received: from nbd.name ([46.4.11.11]:52859 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751045Ab1BDLlP (ORCPT ); Fri, 4 Feb 2011 06:41:15 -0500 Message-ID: <4D4BE5D7.8090202@openwrt.org> Date: Fri, 04 Feb 2011 12:41:11 +0100 From: Felix Fietkau MIME-Version: 1.0 To: Dmitry Torokhov CC: Miklos Szeredi , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, "John W. Linville" Subject: Re: Wireless regression (was 2.6.38-rc3: FUSE (sshfs) hangs under load) References: <20110201175452.GB518@core.coreip.homeip.net> <20110202165236.GA3178@core.coreip.homeip.net> <20110203065541.GB5592@core.coreip.homeip.net> <20110203194115.GA14159@core.coreip.homeip.net> <20110204064952.GA12914@core.coreip.homeip.net> In-Reply-To: <20110204064952.GA12914@core.coreip.homeip.net> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2011-02-04 7:49 AM, Dmitry Torokhov wrote: > On Thu, Feb 03, 2011 at 11:41:15AM -0800, Dmitry Torokhov wrote: >> On Thu, Feb 03, 2011 at 12:13:24PM +0100, Miklos Szeredi wrote: >> > On Wed, 2 Feb 2011, Dmitry Torokhov wrote: >> > > On Wed, Feb 02, 2011 at 08:52:36AM -0800, Dmitry Torokhov wrote: >> > > > On Wed, Feb 02, 2011 at 12:52:36PM +0100, Miklos Szeredi wrote: >> > > > > On Tue, 1 Feb 2011, Dmitry Torokhov wrote: >> > > > > > Hi, >> > > > > > >> > > > > > After installing 2.6.38-rc3 (plus a few input patches) sshfs started to >> > > > > > misbehave on me under load. It starts off fine but when I try to compile >> > > > > > a few modules against kernel sources residing on the other box the >> > > > > > processes go into 'D' state and just sit there doing nothing. >> > > > > >> > > > > Can you please post a stack trace from SysRq-T? >> > > > > >> > > > > ... >> > > >> > > OK, so here are the stack traces you requested. First one is snapshot of >> > > when compile got stuck, the 2nd one is when I interrupted make which >> > > caused gcc to go to 'D' state. >> > >> > There doesn't appear anything abnormal there. >> > >> > It's going into D state after it has received an interrupt and sent it >> > along to the userspace filesystem. Then it will go into >> > uninterruptible sleep until the answer is received. >> > >> > So the hang is because the answer to an open request is not being >> > received. I can't tell where it got stuck, apparently not anywhere on >> > the local machine. >> > >> > Can you please get a log from sshfs with "-odebug,sshfs_debug" and >> > redirect stderr to a file? That might tell a bit more about the >> > situation. Or it might not... >> >> Hmm, it might be just the network itself, last night mutt in ssh session >> froze on me as well. I guess I'll just have to finish my bisect >> exercise. >> > > I finished bisecting and it turned out that the problematic commit > happened to be in wireless (I have iwl3945): > > commit 4cd06a344db752f513437138953af191cbe9a691 > Author: Felix Fietkau > Date: Sat Dec 18 19:30:49 2010 +0100 > > mac80211: skip unnecessary pskb_expand_head calls > > If the skb is not cloned and we don't need any extra headroom, there > is no point in reallocating the skb head. > > Signed-off-by: Felix Fietkau > Signed-off-by: John W. Linville > > With this commit reverted from 2.6.38-rc3 I can not reproduce sshfs > getting stuck here. I really don't see how this commit could be causing these issues, and I'm not aware of any similar issues affecting other drivers. - Felix