Date: Tue, 31 May 2011 15:16:05 -0700 From: mdf@FreeBSD.org To: "Kenneth D. Merry" <ken@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r222537 - in head/sys: kern sys Message-ID: <BANLkTimh=ND77iP95dTR0ZaXJJCBFATQuQ@mail.gmail.com> In-Reply-To: <20110531221122.GA58836@nargothrond.kdm.org> References: <201105311729.p4VHTwrZ033296@svn.freebsd.org> <BANLkTim1AQQj1BfqHtYfPWrvaQBp41qDNw@mail.gmail.com> <20110531214618.GA57498@nargothrond.kdm.org> <BANLkTinThaAeP9cAVpoGxpSNq2zn%2Ba-P6Q@mail.gmail.com> <20110531221122.GA58836@nargothrond.kdm.org>
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On Tue, May 31, 2011 at 3:11 PM, Kenneth D. Merry <ken@freebsd.org> wrote: > On Tue, May 31, 2011 at 15:02:37 -0700, mdf@FreeBSD.org wrote: >> On Tue, May 31, 2011 at 2:46 PM, Kenneth D. Merry <ken@freebsd.org> wrot= e: >> > On Tue, May 31, 2011 at 14:00:18 -0700, mdf@FreeBSD.org wrote: >> >> On Tue, May 31, 2011 at 10:29 AM, Kenneth D. Merry <ken@freebsd.org> = wrote: >> >> > Author: ken >> >> > Date: Tue May 31 17:29:58 2011 >> >> > New Revision: 222537 >> >> > URL: http://svn.freebsd.org/changeset/base/222537 >> >> > >> >> > Log: >> >> > ?Fix apparent garbage in the message buffer. >> >> > >> >> > ?While we have had a fix in place (options PRINTF_BUFR_SIZE=3D128) = to fix >> >> > ?scrambled console output, the message buffer and syslog were still= getting >> >> > ?log messages one character at a time. ?While all of the characters= still >> >> > ?made it into the log (courtesy of atomic operations), they were of= ten >> >> > ?interleaved when there were multiple threads writing to the buffer= at the >> >> > ?same time. >> >> >> >> This seems to panic my box with "lock "msgbuf" 0xfffffe0127ffffe0 >> >> already initialized". >> >> >> >> Unfortunately, though I booted with a fresh CURRENT this morning >> >> successfully, both /boot/kernel and /boot/kernel.old give this panic. >> >> To add insult to injury, when the kernel drops into the debugger, my >> >> keyboard input no longer works so I can't get a stack, etc. >> > >> > Uh-oh! >> > >> >> So: >> >> >> >> 1) Is there anything else I can do to help debug this? >> >> 2) how can I resurrect this box without a reinstall? >> >> >> >> I will try to repro on a virtual machine so I have a snapshot to come= back to. >> > >> > My guess is that this is an issue with the message buffer reinitializa= tion >> > path. ?lock_init() (called by mtx_init()) has an assert to make sure t= hat >> > the lock is initialized, and that is just a flag check. >> > >> > Since the spin lock is part of the message buffer structure, if it is = held >> > over from a previous boot, the LO_INITIALIZED flag may still be set. >> > >> > Try power cycling the machine. ?If it is an issue with re-initializati= on, >> > that should clear the memory and allow you to boot. >> >> Hmm, apparently my previous presses of the power button weren't long >> enough. =A0I let it sit off for 20 seconds and it boots okay now. > > Okay, so it probably is the re-initialization code. =A0Can you try this p= atch > and see if it survives a warm boot? =A0I also changed the initialization > path, so we don't get tripped up by garbage left in memory. This patch survived a warm reboot (shutdown -r now). > Also, does the debugger work now that it has booted successfully? The debugger (or rather, my keyboard in the debugger) works on a successful boot. I used sysctl debug.kdb.enter=3D1 to test it. Thanks, matthew
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