From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 2/3] netpoll: rework skb transmit queue Date: Fri, 20 Oct 2006 14:41:53 -0700 Message-ID: <20061020144153.2bbeaf9d@dxpl.pdx.osdl.net> References: <20061020.134209.85688168.davem@davemloft.net> <200610202301.29859.ak@suse.de> <20061020.140859.95896187.davem@davemloft.net> <200610202316.03940.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from smtp.osdl.org ([65.172.181.4]:3972 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S2992753AbWJTVmO (ORCPT ); Fri, 20 Oct 2006 17:42:14 -0400 To: Andi Kleen In-Reply-To: <200610202316.03940.ak@suse.de> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, 20 Oct 2006 23:16:03 +0200 Andi Kleen wrote: > On Friday 20 October 2006 23:08, David Miller wrote: > > From: Andi Kleen > > Date: Fri, 20 Oct 2006 23:01:29 +0200 > > > > > netpoll always played a little fast'n'lose with various locking rules. > > > > The current code is fine, it never reenters ->poll, because it > > maintains a "->poll_owner" which it checks in netpoll_send_skb() > > before trying to call back into ->poll. > > I was more thinking of reentry of the interrupt handler in > the driver etc. A lot of them also do printk, but that is fortunately > caught higher level. > > -Andi One problem is that with netconsole the NAPI poll routine can be called with IRQ's disabled. This means that calls to dev_kfree_skb() are incorrect in this context. The driver would have to use dev_kfree_skb_any() instead.