Minidumps in -STABLE and "smaller than physical memory"

[Ruslan Ermilov]

On Thu, Jan 31, 2008 at 01:35:39PM +0100, Peter Holm wrote:
> On Wed, Jan 30, 2008 at 08:06:40PM +0300, Ruslan Ermilov wrote:
> > On Thu, Sep 21, 2006 at 05:16:36PM +0200, Peter Holm wrote:
> > > On Thu, Sep 21, 2006 at 05:15:47PM +0400, Ruslan Ermilov wrote:
> > > > On Thu, Sep 21, 2006 at 11:14:33AM +0100, Gavin Atkinson wrote:
> > > > > On Thu, 2006-09-21 at 11:44 +0300, Dmitry Pryanishnikov wrote:
> > > > > > Hello!
> > > > > > 
> > > > > >    I've noticed (with the 2-day old RELENG_6) that I still can't configure my
> > > > > > 256Mb swap partition as a dump device for i386 machine with 1Gb RAM despite
> > > > > > having minidumps enabled:
> > > > > > 
> > > > > > root at test2# sysctl debug.minidump
> > > > > > debug.minidump: 1
> > > > > > root at test2# dumpon -v /dev/ad0s3b
> > > > > > /dev/ad0s3b is smaller than physical memory
> > > > > > 
> > > > > > Am I correctly understand that minidumps should lift the restriction
> > > > > > 
> > > > > >  	sizeof(dumpdev) >= sizeof(RAM)
> > > > > 
> > > > > Yes.
> > > > > 
> > > > > http://www.freebsd.org/cgi/cvsweb.cgi/src/sbin/dumpon/dumpon.c.diff?r1=1.22&r2=1.23
> > > > > needs to be MFC'd.
> > > > > 
> > > > I sent an MFC request to re at .
> > > > 
> > > 
> > > >From time to time I've had problems with minidumps on HEAD. Calling
> > > doadump() seems to work ok, but after a reset there's no dump. I
> > > haven't had time to test this systematically. Has anybody else seen
> > > this problem?
> > > 
> > I think this was the same problem as was diagnosed (minidumps + amd64 +
> > SMP).  Though it's not fixed yet, it's understood and its damage is
> > avoided.
> > 
> No, this was and is i386. After changing "doadump;reset" to
> doadump;continue" it would seem that the dumps has a higher chance
> of making it to the disk.
> 
"call doadump" and the "continue" renders my systems unusable
due to a regression made in kern_shutdown.c,v 1.122.  I'm now
living with this patch:

%%%
Index: kern_shutdown.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_shutdown.c,v
retrieving revision 1.189
diff -u -p -r1.189 kern_shutdown.c
--- kern_shutdown.c	28 Jan 2008 19:04:07 -0000	1.189
+++ kern_shutdown.c	1 Feb 2008 15:40:38 -0000
@@ -249,6 +249,7 @@ doadump(void)
 	else
 #endif
 		dumpsys(&dumper);
+	dumping--;
 }
 
 static int
%%%


Cheers,
-- 
Ruslan Ermilov
ru at FreeBSD.org
FreeBSD committer