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Date:      Sun, 14 May 1995 03:33:14 +0300
From:      Heikki Suonsivu <hsu@cs.hut.fi>
To:        Bruce Evans <bde@zeta.org.au>
Cc:        freebsd-bugs@freefall.cdrom.com, hsu@cs.hut.fi
Subject:   Re: i386/395: CRITICAL PROBLEM: spl functions implemented incorrectly
Message-ID:  <199505140033.AA15782@cardhu.cs.hut.fi>
In-Reply-To: <199505121955.FAA02157@godzilla.zeta.org.au>
References:  <199505121955.FAA02157@godzilla.zeta.org.au>

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Bruce Evans writes:
 > >s = splsomething();
 > >if (foo) {
 > >	... something, which does verifyably not modify foo ...
 > >	if (foo->bar) /* foo is NULL or garbage here, generating kernel
 > > 			 page fault. */
 > >}
 > >splx(s);

 > >can't remember which one (there are probably several open ones for me in
 > >GNATS, with stack traces and later ones with some kgdb wanderarounds).

 > There seems to be only one relevant one:

 > >>Synopsis:       (apparently) bounce buffer code gets used on 32bit bus

I thought there would be more, but maybe I just didn't send them or they
got lost somewhere...

The FreeBSD 1 "NFS server foo is alive again" problem wasn't reported as PR
but by mail to freebsd-bugs, its old story (but still valid, almost every
time one of the nfs servers panics, the FreeBSD 1 goes with it after the
server comes up).

 > >	bounce buffer code shouldn't be called in this machine,
 > >doesn't it say "enabling bounce buffer code" in boot on those which
 > >need it?

 > The bt driver always sets SDEV_BOUNCE :-(.

I took the whole thing out to see if it affected the problem.  It didn't,
but exchanging the motherboard from P60 to P90 seems to reduce the
frequency of problems.

-- 
Heikki Suonsivu, T{ysikuu 10 C 83/02210 Espoo/FINLAND,
hsu@cs.hut.fi  home +358-0-8031121 work -4513377 fax -4555276  riippu SN



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