----- Original Message ----- > On Tue, Feb 18, 2014 at 12:27 PM, Dave Anderson <anderson@xxxxxxxxxx> wrote: > > > > > > ----- Original Message ----- > >> > > >> > But if I try that value with your patch applied, it fails in the same > >> > manner > >> > as if I don't use the --kaslr option at all: > >> > > >> > $ crash --kaslr 0x19000000 vmlinux vmcore > >> > > >> > crash 7.0.5rc12 > >> > Copyright (C) 2002-2014 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) 7.6 > >> > Copyright (C) 2013 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 "x86_64-unknown-linux-gnu"... > >> > > >> > WARNING: could not find MAGIC_START! > >> > WARNING: cannot read linux_banner string > >> > crash: vmlinux and vmcore do not match! > >> > > >> > Usage: > >> > > >> > crash [OPTION]... NAMELIST MEMORY-IMAGE (dumpfile form) > >> > crash [OPTION]... [NAMELIST] (live system form) > >> > > >> > Enter "crash -h" for details. > >> > $ > >> > > >> > Any ideas? I can give you the vmlinux/vmcore/kallsyms triplet if you'd > >> > like. > >> > >> As far as why the offset wasn't present, sorry about that. I guess > >> our tool chain is a bit more different than upstream, I've had a bit > >> of trouble generating kdump files for upstream. > >> > >> Your manual calculations look correct to me though and it should work. > >> If you can send me the vmlinux/vmcore triplet (I don't think I need > >> the kallsyms) then I will look at this today. Can you post it > >> somewhere I can download it? > >> > >> Sorry for the delay I was on vacation. > >> > >> thanks, > >> Andy > > > > Actually you do need the kallsyms... > > > > As I mentioned to Kees in an earlier message, the display of > > the offset in the kernel log will not be done in the case of > > kdump-enabled kernels, because crash_kexec() is called before > > the panic_notifier list is executed, and crash_kexec() does > > not return. > > > > I've put the triplet here: > > > > http://people.redhat.com/anderson/kaslr > > > > Note that we can only create ELF vmcores with kASLR because the > > makedumpfile > > facility also needs to be fixed to handle kASLR kernels. > > > > Anyway, as it turns out, the offset is not 0x19000000 (&_text - > > __START_KERNEL), > > but rather it is 0x18000000, which is the difference between the > > kallsyms symbol values and those compiled into the vmlinux file. > > With that --kaslr offset value, the crash session comes up OK. > > Oh, hm. Is the difference maybe due to CONFIG_PHYSICAL_START some how? > > -Kees Right -- I didn't create the kernel, but I presume both CONFIG_PHYSICAL_START and CONFIG_PHYSICAL_ALIGN are both 16MB, resulting in: $ grep _text kallsyms | head -1 ffffffff99000000 T _text $ nm -Bn vmlinux | grep _text | head -1 ffffffff81000000 T _text $ Dave -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
