Date: Mon, 18 Mar 2002 10:31:51 -0800 From: Alfred Perlstein <bright@mu.org> To: John Baldwin <jhb@FreeBSD.org> Cc: Robert Watson <rwatson@FreeBSD.ORG>, smp@FreeBSD.ORG, current@FreeBSD.ORG, hitmaster2k@yahoo.com, phk@FreeBSD.ORG, tanimura@r.dl.itc.u-tokyo.ac.jp, Munehiro Matsuda <haro@h4.dion.ne.jp> Subject: Re: -current lock warning... Message-ID: <20020318183151.GA22622@elvis.mu.org> In-Reply-To: <XFMail.20020318132404.jhb@FreeBSD.org> References: <Pine.NEB.3.96L.1020317120811.965J-100000@fledge.watson.org> <XFMail.20020318132404.jhb@FreeBSD.org>
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* John Baldwin <jhb@FreeBSD.org> [020318 10:24] wrote: > > On 17-Mar-2002 Robert Watson wrote: > > > > On Sun, 17 Mar 2002, Alfred Perlstein wrote: > > > >> * Munehiro Matsuda <haro@h4.dion.ne.jp> [020317 06:36] wrote: > >> > > >> > PS. I got another message that happend when I ^C'ed a buildworld earlier, > >> > with same kernel. May be it should go to Alfred Perlstein? > >> > > >> > lock order reversal > >> > 1st 0xc198eec0 pipe mutex @ ../../../kern/sys_pipe.c:779 > >> > 2nd 0xc0367fe0 Giant @ ../../../i386/i386/trap.c:716 > >> > >> I think there's a place where the pipe can fault on an address while > >> copying, I'll take a look at this. > > > > Are there any assertions that should be in place for copyin/copyout > > requring fault handling? It sounds like somewhere we need to assert that > > Giant is held... > > More correct is that probably no locks other than Giant should be held for > copyin/copyout. s/probably/definetly. Can you please provide a "blessed" API for raising and lowering a "can't block" count in the thread? This can be used in copyout, copyin, and a bunch of vm and buffer ops to make sure we aren't calling them with mutexes held. -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' Tax deductible donations for FreeBSD: http://www.freebsdfoundation.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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