Date: Mon, 18 Mar 2002 13:42:58 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Alfred Perlstein <bright@mu.org> Cc: Munehiro Matsuda <haro@h4.dion.ne.jp>, tanimura@r.dl.itc.u-tokyo.ac.jp, phk@FreeBSD.ORG, hitmaster2k@yahoo.com, current@FreeBSD.ORG, smp@FreeBSD.ORG, Robert Watson <rwatson@FreeBSD.ORG> Subject: Re: -current lock warning... Message-ID: <XFMail.20020318134258.jhb@FreeBSD.org> In-Reply-To: <20020318183151.GA22622@elvis.mu.org>
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On 18-Mar-2002 Alfred Perlstein wrote: > * 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. *sigh* I've never objected to it and even provided you with tips on how to implement it. What more do you want? I'm not really sure we need it though to be honest as the implicit checks done by witness will probably ensure this for us. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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