Date: Tue, 7 Jan 2003 09:24:42 +0000 From: Doug Rabson <dfr@nlsystems.com> To: Marcel Moolenaar <marcel@xcllnt.net>, Arun Sharma <arun.sharma@intel.com> Cc: freebsd-ia64@FreeBSD.ORG Subject: Re: unaligned fault in pmap_find_vhpt Message-ID: <200301070924.42508.dfr@nlsystems.com> In-Reply-To: <20030104043524.GA2059@dhcp01.pn.xcllnt.net> References: <200301032303.gBQJBOs00863@unix-os.sc.intel.com> <20030104043524.GA2059@dhcp01.pn.xcllnt.net>
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On Saturday 04 January 2003 4:35 am, Marcel Moolenaar wrote: > On Fri, Jan 03, 2003 at 03:03:14PM -0800, Arun Sharma wrote: > > I saw a kernel mode unaligned fault during a compilation workload > > yesterday on an SMP 5.0-RC1 kernel. The fault happened here: > > > > 0xe000000000aad660 <pmap_find_vhpt+80>: > > > > More info below. It looks like the pte_chain is getting corrupted > > somehow. What is the locking scheme being used to protect pte > > collision chains on an SMP kernel ? > > We don't really have a consistent locking scheme. We walk and > update the VHPT from IVA interrupt code as well. Under high > load, a SMP kernel corrupts process space. I haven't seen the > unaligned fault you mention. The IVA only updates the contents of the VHPT head entry (which is=20 always a copy of some element of the pte_chain). It never edits the=20 chain but I can see it getting confused if someone else edits the chain=20 while the IVA is walking it. --=20 Doug Rabson=09=09=09=09Mail: dfr@nlsystems.com =09=09=09=09=09Phone: +44 20 8348 6160 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-ia64" in the body of the message
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