Date: Sat, 23 Jan 1999 11:55:49 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Peter Wemm <peter@netplex.com.au> Cc: current@FreeBSD.ORG Subject: Re: panic: found dirty cache page 0xf046f1c0 Message-ID: <199901231955.LAA48625@apollo.backplane.com> References: <199901231943.DAA00782@spinner.netplex.com.au>
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:[..]
:> > Try changing the panic in vm/vm_page.c to a printf() (
:>
:> I'll do that.
:
:BTW; what are the dangers of this? lost disk writes or corruption? Can
:we (as a workaround) push the page that we found back onto a dirty queue
:and try again after some diagnostics?
That's ok, don't worry about it... Doug's debug output gives me the
same info.
:It crashed in uniprocessor mode about 60 seconds after sending this mail.
:It's got a really trimmed down kernel config and no modules loaded or in
:use. I have not disabled softupdates yet, that's next.
I don't get it.... why can't I reproduce this problem?
Can you email me your kernel configuration? Are you using any
special devices like vn or something ?
:Oh, one other thing that occurred to me.. Under 4.0-current, I regularly
:(ie: within 30 seconds of boot) get if_de tranmitter underflows. My
:console corruption was happening at the instant that de0 was being
:configured with ifconfig. exmh is running to a remote display over that
:de0 interface.
:
:Under Jan 16 3.0-current, I do not get that tranmitter underflow..
:
:The only thin I can think of about if_de that's unusual that is VM related
:(apart from the complexity of the code) is that it uses configmalloc(). I
:wonder if this is somehow setting the scene for the later failures? It's
:certainly suspicious that has done strange things when being ifconfig'ed,
:including things like trashing the serial console on no less than a dozen
:occasions.
:
:Cheers,
:-Peter
Hmmm.. HMMMMMM. contigmalloc, eh? You might be onto something here.
I will investigate it.
The problem was are having is that, somehow, a vm_page_t in the PQ_CACHE
is being set dirty.
Sinc vm_page_cache() panics if m->dirty is set, then m->dirty must be getting
set *after* the page has been moved to the cache.
contigmalloc() looks suspicious.
-Matt
Matthew Dillon
<dillon@backplane.com>
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