From owner-cvs-src@FreeBSD.ORG Tue Sep 20 19:50:17 2005 Return-Path: X-Original-To: cvs-src@FreeBSD.org Delivered-To: cvs-src@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6352B16A41F; Tue, 20 Sep 2005 19:50:17 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from mv.twc.weather.com (mv.twc.weather.com [65.212.71.225]) by mx1.FreeBSD.org (Postfix) with ESMTP id B2B5843D45; Tue, 20 Sep 2005 19:50:16 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from [10.50.41.233] (Not Verified[10.50.41.233]) by mv.twc.weather.com with NetIQ MailMarshal (v6, 0, 3, 8) id ; Tue, 20 Sep 2005 16:05:58 -0400 From: John Baldwin To: "M. Warner Losh" Date: Tue, 20 Sep 2005 15:51:09 -0400 User-Agent: KMail/1.8 References: <200509190310.j8J3ALgt095979@repoman.freebsd.org> <20050919055028.GC65954@ip.net.ua> <20050919.083146.105425670.imp@bsdimp.com> In-Reply-To: <20050919.083146.105425670.imp@bsdimp.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200509201551.11396.jhb@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, ru@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/an if_an.c src/sys/dev/arl if_arl_isa.c src/sys/dev/awi if_awi_pccard.c src/sys/dev/cm if_cm_isa.c src/sys/dev/cnw if_cnw.c src/sys/dev/cp if_cp.c src/sys/dev/cs if_cs.c src/sys/dev/ed if_ed.c src/sys/dev/em if_em.c ... X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Sep 2005 19:50:17 -0000 On Monday 19 September 2005 10:31 am, M. Warner Losh wrote: > In message: <20050919055028.GC65954@ip.net.ua> > > Ruslan Ermilov writes: > : Hi, > : > : On Mon, Sep 19, 2005 at 03:10:21AM +0000, Warner Losh wrote: > : > imp 2005-09-19 03:10:21 UTC > : > > : > FreeBSD src repository > : > > : > Modified files: > : > sys/dev/an if_an.c > : > : [...] > : > : > sys/dev/xe if_xe_pccard.c > : > Log: > : > Make sure that we call if_free(ifp) after bus_teardown_intr. Since > : > we could get an interrupt after we free the ifp, and the interrupt > : > handler depended on the ifp being still alive, this could, in theory, > : > cause a crash. Eliminate this possibility by moving the if_free to > : > after the bus_teardown_intr() call. > : > : I'm going into more details in my other reply to your ed(4) commit, > : but I'm pretty sure you're attacking a wrong problem here. Most > : drivers don' assume and will behave badly (read: panic) if foo_intr() > : is called after foo_stop() (foo_stop() disables interrupts and > : usually frees some resources needed by code called from foo_intr()). > : A better fix that I had in mind (and that I think jhb@ has suggested) > : would be to return from foo_intr() quickly if IFF_DRV_RUNNING is not > : set. Can you reproduce the problem that you mention on real hardware? > > You can't test IFF_DRV_RUNNING in memory that's already been freed. > > Warner Then do this: foo_stop(); callout_drain(); ether_ifdetach(); bus_teardowin_intr(); if_free(); Regarding other comments I saw today on some e-mail or another, I do think that to make the locking sane, we might should push the checks for IFF_DRV_RUNNING down into the foo_start() routines rather than doing it in the network layer where the driver lock isn't held. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org