Re: [Crash-utility] crash: cannot determine length of symbol: log_end

----- Original Message ----- > > Hey David, > > > > I just upgraded a dev box to v3.5-rc1 and now crash doesn't work. Have > > you seen this before? > > > > crash 6.0.7 > > Copyright (C) 2002-2012 Red Hat, Inc. > > Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation > > Copyright (C) 1999-2006 Hewlett-Packard Co > > Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited > > Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. > > Copyright (C) 2005, 2011 NEC Corporation > > Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. > > Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. > > This program is free software, covered by the GNU General Public License, > > and you are welcome to change it and/or distribute copies of it under > > certain conditions. Enter "help copying" to see the conditions. > > This program has absolutely no warranty. Enter "help warranty" for > > details. > > > > GNU gdb (GDB) 7.3.1 > > Copyright (C) 2011 Free Software Foundation, Inc. > > License GPLv3+: GNU GPL version 3 or later > > <http://gnu.org/licenses/gpl.html> > > This is free software: you are free to change and redistribute it. > > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > > and "show warranty" for details. > > This GDB was configured as "i686-pc-linux-gnu"... > > > > SYSTEM MAP: /boot/System.map-3.5.0-rc1-1.2-desktop > > DEBUG KERNEL: /root/xfs/vmlinux > > DUMPFILE: vmcore > > CPUS: 4 > > DATE: Tue Jun 5 15:13:35 2012 > > UPTIME: 01:58:35 > > LOAD AVERAGE: 2.06, 1.61, 1.77 > > TASKS: 90 > > NODENAME: nfs7 > > RELEASE: 3.5.0-rc1-1.2-desktop > > VERSION: #20 SMP PREEMPT Tue Jun 5 12:56:22 CDT 2012 > > MACHINE: i686 (2399 Mhz) > > MEMORY: 6 GB > > PANIC: > > crash: cannot determine length of symbol: log_end > > > > > > > > I had been using crash 6.0.6 on this machine on a regular basis until > > upgrading the kernel. I expect if I go back to the older kernel it will > > work again. Any suggestions? More info I can provide? > > > > Thanks, > > Ben > > Right, this recent upstream kernel commit has re-designed the log buffer > scheme: > > commit 7ff9554bb578ba02166071d2d487b7fc7d860d62 > Author: Kay Sievers <kay vrfy org> > Date: Thu May 3 02:29:13 2012 +0200 > > printk: convert byte-buffer to variable-length record buffer > > Eventually I, or somebody on the crash-utility mailing list, will get around > to updating crash to handle the new scheme. > > The only thing you can do to work around it for now is to hack kernel.c > and just force the dump_log() function to return immediately: > > void > dump_log(int msg_level) > { > int i, len, tmp; > ulong log_buf, log_end; > char *buf; > char last; > ulong index; > struct syment *nsp; > int log_wrap, loglevel, log_buf_len; > > + return; > > if (symbol_exists("log_buf_len")) { > get_symbol_data("log_buf_len", sizeof(int), &log_buf_len); > get_symbol_data("log_buf", sizeof(ulong), &log_buf); > } else { > ... > > Dave I have a fix queued for crash-6.0.8. I should also mention that a more reasonable workaround to the hack above would be to simply invoke the session with "crash -s ...". In that case, the session will come up OK -- although the "sys" and "log" commands will result in the same (but non-fatal) error message.