On Tue, 2006-04-25 at 14:42 -0400, Dave Anderson wrote: > Badari Pulavarty wrote: > > > Hi, > > > > I get following crash warnings on x86-64 machine. Wondering why ? > > And also, its not showing stacks correctly. > > > > Thanks, > > Badari > > > > # ./crash /var/log/dump/2006-04-24-08:02/vmcore /usr/src/linux/vmlinux > > > > crash 4.0-2.23 > > Copyright (C) 2002, 2003, 2004, 2005, 2006 Red Hat, Inc. > > Copyright (C) 2004, 2005, 2006 IBM Corporation > > Copyright (C) 1999-2006 Hewlett-Packard Co > > Copyright (C) 2005 Fujitsu Limited > > Copyright (C) 2005 NEC Corporation > > Copyright (C) 1999, 2002 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 6.1 > > Copyright 2004 Free Software Foundation, Inc. > > GDB 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. > > Type "show copying" to see the conditions. > > There is absolutely no warranty for GDB. Type "show warranty" for > > details. > > This GDB was configured as "x86_64-unknown-linux-gnu"... > > > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > WARNING: possibly bogus exception frame > > KERNEL: /usr/src/linux/vmlinux > > DUMPFILE: /var/log/dump/2006-04-24-08:02/vmcore > > CPUS: 2 > > DATE: Mon Apr 24 08:02:03 2006 > > UPTIME: 00:06:31 > > LOAD AVERAGE: 0.00, 0.00, 0.00 > > TASKS: 63 > > NODENAME: elm3a242 > > RELEASE: 2.6.16-20-smp > > VERSION: #1 SMP Mon Apr 10 04:51:13 UTC 2006 > > MACHINE: x86_64 (3000 Mhz) > > MEMORY: 4.6 GB > > PANIC: "SysRq : Trigger a crashdump" > > PID: 0 > > COMMAND: "swapper" > > TASK: ffffffff80335340 (1 of 2) [THREAD_INFO: > > ffffffff8045c000] > > CPU: 0 > > STATE: TASK_RUNNING (ACTIVE) > > > > crash> bt > > PID: 0 TASK: ffffffff80335340 CPU: 0 COMMAND: "swapper" > > #0 [ffffffff8045dee8] schedule at ffffffff802cf6fa > > It's hard to debug this from here, but... > > Two things look strange, (1) it's not finding the proper starting > point for the panicking (?) idle thread -- and possibly not even finding > the correct panic task, and (2) the "possibly bogus exception > frame" messages are due to the x86_64.c x86_64_eframe_verify() > function finding something irregular in the exception frames (the > pt_regs) of several processes while it made a search of all > possible processes for the panic task. > > I would guess that if you do a "foreach bt", you will see the > "possibly bogus" messages associated with the user-space > exception frames of all user-space generated processes > (i.e. not kernel threads). It would be interesting to see what > those frames look like, and why they are considered strange, > probably a new cs or ss value that's never been used before? > > As far as the determination of the panic task, I'm presuming > that this was generated from a kdump dumpfile. The netdump.c > get_netdump_panic_task() function, which has a bunch of > kdump-specific code, is failing to find the panic task from the > data in the ELF header notes. Running "crash -d1 ..." will indicate > how crash is trying to determine the panic task. I don't know > whether the idle task was even the one that took the sysrq, > or whether it just defaulted to that task because it couldn't find > any other likely suspects. You'll have to debug it from your > end, starting from get_netdump_panic_task(). > > Dave Dave, I added little debug and found that x86_64_eframe_verify() returns FALSE to due to !(rflags & 0x2) (rflags = 0x200 in this dump). Given that "crash" runs fine on live machine, I am going to assume that its a problem with kdump format for now :( Thanks, Badari
