Date: Tue, 11 Jan 2000 22:18:44 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Brian Fundakowski Feldman <green@FreeBSD.ORG> Cc: Stephen McKay <syssgm@detir.qld.gov.au>, freebsd-current@FreeBSD.ORG, dt@FreeBSD.ORG Subject: Re: Crash from ^T during heavy paging Message-ID: <Pine.BSF.4.10.10001112139030.16099-100000@alphplex.bde.org> In-Reply-To: <Pine.BSF.4.10.10001110327150.39255-100000@green.dyndns.org>
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On Tue, 11 Jan 2000, Brian Fundakowski Feldman wrote: > On Mon, 10 Jan 2000, Stephen McKay wrote: > > > The problem is that calcru() thinks that P_INMEM means that the proc > > structure is fully and accurately populated. But P_INMEM is one of the > > first flags set. > > > > So, calcru() and possibly some other places, are looking at a struct proc > > before it's all there. What's the "proper" way to do it? > > It should really be one of the _last_ flags set, if it's to mean anything. > I don't know how to explain the prevalance of race conditions in the old > code, except to say it probably has to do with not planning ahead. > [patch deleted] I broke calcru() with the monotonicity fixes (kern_resource.c rev.1.45 (1999/03/13). Accessing p->p_stats at interrupt time is only valid if p == curproc. Fix: move the new monotonicity fields from struct pstats to struct proc. I only put them in struct pstats because they logically go with some fields in struct rusage. P_INMEM is probably not supposed to work in interrupt contexts. Checking it in ttyinfo() is a wrong fix for the bug in calcru(). It was committed in tty.c rev.1.119 (1999/05/22). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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