Deadlocks with recent SMP current

Craig Boston craig at
Fri Aug 13 15:52:40 PDT 2004

On Fri, Aug 13, 2004 at 12:16:57PM +0200, 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.

Just a "me too", I have an SMP system running 8/5/04 current that hard
locks randomly.  It seems to happen more often when there is moderate
I/O load, such as extracting a tar file or compiling a kernel, but it
has happened while almost completely idle too.  DDB is in the kernel but
cannot be accessed as the system is frozen solid (I do not have NMI
capability on this machine).

I'm using 4BSD scheduler and get the warning about preemption being

I'm currently running with kern.smp.disabled="1" as that is the only way
the system is at all stable :(

Oddly enough, it seems to be more responsive without the second processor
running than with it -- possibly due to preemption being off.


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