Date: Tue, 13 Jan 2009 16:10:50 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Pete French <petefrench@ticketswitch.com> Cc: dougb@freebsd.org, freebsd-stable@freebsd.org, kometen@gmail.com Subject: Re: Big problems with 7.1 locking up :-( Message-ID: <alpine.BSF.2.00.0901131607580.95856@fledge.watson.org> In-Reply-To: <E1LMl1D-0000cm-9v@dilbert.ticketswitch.com> References: <E1LMl1D-0000cm-9v@dilbert.ticketswitch.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 13 Jan 2009, Pete French wrote: >> I can't (fortunately) make it lock up. I have a DL360 G5 which is unused >> atm. and can test on it if needed. > > Would it be possible to install that under amd64 and hammer it with DNS > requests ? I have been trying to think what the difference might be between > my webservers and the machines which are freezing, and the opnly one I an > come up with is UDP traffic as the locking machines are serving DNS and also > NFS. There are significant changes in UDP locking between 7.0 and 7.1, so it could be that we're looking at a regression there. If you're able to reproduce this reliably, it might well be worth doing a little search-and-replace in udp_usrreq.c along the following lines: INP_RLOCK_ASSERT -> INP_WLOCK_ASSERT INP_RLOCK -> INP_WLOCK INP_RUNLOCK -> INP_WUNLOCK However, before making these changes for debugging purposes, make sure it's 100% reproduceable without them in the configuration so that we don't find ourselves barking up the wrong tree. Normally deadlocks along these lines *do* allow breaking into the debugger from a serial console, but since there are significant changes here in 7.1 it is worth trying to see if this might be related. Robert N M Watson Computer Laboratory University of Cambridge
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?alpine.BSF.2.00.0901131607580.95856>