Date: Fri, 13 Aug 2004 14:13:19 -0600 From: Scott Long <scottl@samsco.org> To: Doug White <dwhite@gumbysoft.com> Cc: freebsd-current@freebsd.org Subject: Re: Deadlocks with recent SMP current Message-ID: <411D20DF.2000503@samsco.org> In-Reply-To: <20040813102922.E93695@carver.gumbysoft.com> References: <20040813121208.M31181@cvs.imp.ch> <20040813102922.E93695@carver.gumbysoft.com>
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Doug White wrote:
> On Fri, 13 Aug 2004, Martin Blapp wrote:
>
>
>>Since yesterday I'm getting complete deadlocks. This time unrelated
>>the servers are nor loaded at all, the just freeze after a while.
>>No break into DDB possible at all.
>
>
> Welcome to the club; I've been having them on my -curent builder since Aug
> 4. I'm going to set up a duplicate box and start binary-searching for the
> offending commit(s).
>
> Preemption is the default, disabled.
>
> My box is a dual-600MHz P3 with 1GB RAM and running kde. A make -j3
> buildworld will lock it up 75% of the time. It'll survive a nonparallel
> build, and it'll survive a kernel build.
>
> Haven't tried WITNESS+INVARIANTS yet since it really dogs the machine. :)
>
Can you try the patch below? It's really only a band-aid, but might
make things usable for now. Also, are more lockups being seen under
ULE or under 4BSD. There was a recent change to ULE (rev 1.120 of
sched_ule.c) that seems to have aggrivated the scheduler problems on
my test systems.
Scott
Index: kern_switch.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/kern_switch.c,v
retrieving revision 1.78
diff -u -r1.78 kern_switch.c
--- kern_switch.c 10 Aug 2004 00:26:25 -0000 1.78
+++ kern_switch.c 13 Aug 2004 20:11:27 -0000
@@ -345,6 +345,8 @@
return;
}
+ critical_enter();
+
tda = kg->kg_last_assigned;
if ((ke = td->td_kse) == NULL) {
if (kg->kg_idle_kses) {
@@ -441,6 +443,7 @@
CTR3(KTR_RUNQ, "setrunqueue: held: td%p kg%p pid%d",
td, td->td_ksegrp, td->td_proc->p_pid);
}
+ critical_exit();
}
/*
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