Date: Mon, 04 Aug 1997 20:15:55 -0600 From: Steve Passe <smp@csn.net> To: current@freebsd.org Subject: tsleep & KTRACE on SMP Message-ID: <199708050215.UAA13712@Ilsa.StevesCafe.com>
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Hi,
I am debugging PR kern/3835 and find that the problem is in tsleep().
Specifically if the config file contains:
config dumps on wd0
the code to set this up happens in configure() b4 curproc (ie *p) is setup.
configure() maintains the variable 'cold' to deal with this issue. However
when KTRACE is enabled the code in tsleep attempts to use curproc before
testing 'cold':
----------------------------------- cut -----------------------------------
tsleep(ident, priority, wmesg, timo)
{
...
#ifdef KTRACE
if (KTRPOINT(p, KTR_CSW))
ktrcsw(p->p_tracep, 1, 0);
#endif
s = splhigh();
if (cold || panicstr) {
/*
* After a panic, or during autoconfiguration,
* just give interrupts a chance, then just return;
* don't run any other procs or panic below,
* in case this is the idle process and already asleep.
*/
splx(safepri);
splx(s);
return (0);
}
#ifdef DIAGNOSTIC
----------------------------------- cut -----------------------------------
if I move the "ifdef KTRACE" section to after the "if (cold ..." test
the SMP kernel is happy.
Does anyone see why this would be a bad thing to do in the general
(ie UP) case?
Or should I conditionalize the location of the KTRACE code with "ifdef SMP"?
--
Steve Passe | powered by
smp@csn.net | Symmetric MultiProcessor FreeBSD
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