From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [Kgdb-bugreport] [PATCH 2.6.20-rc7] 8139too KGDBoE fix Date: Fri, 23 Feb 2007 22:16:59 +0300 Message-ID: <45DF3DAB.3010902@ru.mvista.com> References: <200701312144.56497.sshtylyov@ru.mvista.com> <45DDBD96.10000@ru.mvista.com> <45DDC7C0.8050100@ru.mvista.com> <200702231238.40474.amitkale@linsyssoft.com> <45DF2E20.305@mvista.com> <20070223110451.44066f09@freekitty> <45DF3BDC.2070806@ru.mvista.com> <20070223111354.2e25db9d@freekitty> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Mark Huth , "Amit S. Kale" , netdev@vger.kernel.org, Mithlesh Thukral , Vitaly Wool To: Stephen Hemminger Return-path: Received: from h155.mvista.com ([63.81.120.155]:42415 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933179AbXBWTRJ (ORCPT ); Fri, 23 Feb 2007 14:17:09 -0500 In-Reply-To: <20070223111354.2e25db9d@freekitty> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello. Stephen Hemminger wrote: >>>>>This thread came up on kgdb-bugreport mailing list. Could you please suggest >>>>>us what's the correct way of fixing this problem? >>>>>1. When running a kgdb on RTL8139 ethernet interface: 8139too driver prints >>>>>too many "Out-of-sync dirty pointer" messages on console and gdb can't >>>>>connect to kgdb stub. These messages can be suppressed, though it still >>>>>results in connection failures frequently. >>>>We think this comes from calling the driver while the queue is stopped. >>>>Drivers should not do horrible things when hard start is called with the >>>>queue stopped, but unfortunately, at this time, at least some drivers >>>>do explode or complain under that condition. >>>The kernel is built on a set of assumptions about calling context. Your >>>out of tree code is violating one of them. Why not check for stopped queue >>>and do some action to try and clear it, that is what netconsole does. >> The queue can't be stopped when the netpoll traffic trapping is enabled >>(cause this effectively bypasses queue control), So, the stopped queue >>indoication doesn't work also -- *that* is the problem. It's not at all >>specific to KGBoE -- only to traffic trapping. > You can't ask a device to send a packet when it has no resources. When traffic trapping is enabled, and driver stops the queue, the __LINK_STATE_XOFF flag does *not* get set, so netif_queue_stopped() resturns *zero*. What may be done in this situation? WBR, Sergei