Date: Fri, 25 May 2007 20:35:21 +0200 From: "Attilio Rao" <attilio@freebsd.org> To: "Joe Marcus Clarke" <marcus@marcuscom.com> Cc: Jeff Roberson <jroberson@chesapeake.net>, Current@freebsd.org Subject: Re: Panic on -CURRENT after LDT changes Message-ID: <3bbf2fe10705251135j2b858529l964bf22285d5554e@mail.gmail.com> In-Reply-To: <46572970.5080201@marcuscom.com> References: <1179962663.75721.6.camel@shumai.marcuscom.com> <20070523165051.G9443@10.0.0.1> <4655D5C1.2010905@FreeBSD.org> <1180022919.10757.24.camel@shumai.marcuscom.com> <3bbf2fe10705240930o10f37febt9fb5f0a46bd193c3@mail.gmail.com> <4657267C.2070306@marcuscom.com> <3bbf2fe10705251116h1a4606fg6250d917247a5143@mail.gmail.com> <46572970.5080201@marcuscom.com>
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2007/5/25, Joe Marcus Clarke <marcus@marcuscom.com>: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Attilio Rao wrote: > > 2007/5/25, Joe Marcus Clarke <marcus@marcuscom.com>: > >> -----BEGIN PGP SIGNED MESSAGE----- > >> Hash: SHA1 > >> > >> Attilio Rao wrote: > >> > 2007/5/24, Joe Marcus Clarke <marcus@marcuscom.com>: > >> >> On Thu, 2007-05-24 at 20:13 +0200, Attilio Rao wrote: > >> >> > Jeff Roberson wrote: > >> >> > > Thanks, Attilio and I will look at this right away. > >> >> > > > >> >> > > Jeff > >> >> > > > >> >> > > On Wed, 23 May 2007, Joe Marcus Clarke wrote: > >> >> > > > >> >> > >> On a -CURRENT build today with Jeff's LDT locking changes, I > >> get an > >> >> > >> instant, reproducible panic by doing: > >> >> > >> > >> >> > >> # cd /usr/src > >> >> > >> # make -DNO_CLEAN buildworld > >> >> > >> > >> >> > >> Backing out the LDT changes to /sys/i386/i386/*machdep* > >> corrects the > >> >> > >> problem. Here is a dmesg and backtrace. In frame 6, it appears > >> >> mdp is > >> >> > >> NULL (i.e. td->td_proc->p_md = 0x0). > >> >> > > >> >> > Did you enable WITNESS/INVARIANTS/INVARIANT_SUPPORT? > >> >> > >> >> No, this kernel does not have WITNESS or INVARIANTS. I can enable > >> those > >> >> tomorrow if that would give you more useful information. > >> > > >> > It would be very appreciated, since I've been unable to reproduce your > >> > panic on a centrino dual core. > >> > >> I'm stopped in the debugger now with WITNESS and friends enabled. Same > >> backtrace as before. I did a "show locks" and I see: > >> > >> exclusive spin mutex descriptor tables r = 0 (0xc08369f8) locked @ > >> /usr/src/sys/i386/i386/sys_machdep.c:629 > >> > >> Please let me know what else you'd like to see while I'm at the > >> debugger. FYI: this is a Pentium 4 with "options SMP" disabled. > > > > This is a multicore? do you have PREEMPTION/FULL_PREEMPTION installed? > > No, single core with PREEMPTION enabled only. Very strange. Could you disable PREEMPTION and see if the error persists? Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein
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