On Tue, May 31, 2011 at 2:46 PM, Kenneth D. Merry <k...@freebsd.org> wrote: > On Tue, May 31, 2011 at 14:00:18 -0700, m...@freebsd.org wrote: >> On Tue, May 31, 2011 at 10:29 AM, Kenneth D. Merry <k...@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=128) 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 often >> > ?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 reinitialization > path. lock_init() (called by mtx_init()) has an assert to make sure that > 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-initialization, > that should clear the memory and allow you to boot.
Hmm, apparently my previous presses of the power button weren't long enough. I let it sit off for 20 seconds and it boots okay now. Thanks, matthew > My testing has been with VMs (under Xen), so the reinit path has probably > not been tested as fully as it should have been. Sorry about that! > > As for the debugger, that's another issue altogether. It does work for me, > but then again if the spin lock initialization is broken for the message > buffer that may affect things. > > Try a cold boot and see if that helps. If so, I think we can probably just > bzero the mutex in msgbuf_reinit() and that will fix things. > > Ken > -- > Kenneth Merry > k...@freebsd.org > _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
