12:30 p.m.
----- Original Message -----
FYI, if you're running with bleeding edge upstream kernels, this
recent commit destroys a fundamental underpinning required by the
crash utility:
commit e8cfbc245e24887e3c30235f71e9e9405e0cfc39
Author: Gargi Sharma <gs051095(a)gmail.com>
Date: Fri Nov 17 15:30:34 2017 -0800
pid: remove pidhash
pidhash is no longer required as all the information can be looked up
from idr tree. nr_hashed represented the number of pids that had been
hashed. Since, nr_hashed and PIDNS_HASH_ADDING are no longer relevant,
it has been renamed to pid_allocated and PIDNS_ADDING respectively.
I'm not sure how the failure will manifest itself, but it certainly will
will fail early on during session initialization.
Here's what happens, in this case running on a Fedora rawhide kernel:
# uname -r
4.15.0-0.rc0.git6.1.fc28.x86_64
It fails with a seemingly unrelated error message because it has
defaulted to using an ancient task-gathering function that was
suitable for kernels back in the pre-pidhash Linux 2.2 era:
# ./crash
crash 7.2.0++
Copyright (C) 2002-2017 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: kernel relocated [208MB]: patching 98688 gdb minimal_symbol values
crash: cannot resolve "init_task_union"
#
When I saw the original
patch postings, I started tinkering with the creation of yet another
function to plug into "tt->refresh_task_table" for the new IDR/radix-tree
scheme, but until I see an actual live kernel and/or vmcore with the patch
above, I've held off on further work on it.
In the meantime, you can use the "crash --active" command line option,
which restricts the task list to those that are registered as the current
task in each per-cpu runqueue.
At least that works:
# ./crash --active
crash 7.2.0++
Copyright (C) 2002-2017 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: kernel relocated [208MB]: patching 98688 gdb minimal_symbol values
KERNEL: /usr/lib/debug/lib/modules/4.15.0-0.rc0.git6.1.fc28.x86_64/vmlinux
DUMPFILE: /dev/crash
CPUS: 8
DATE: Wed Nov 22 18:14:17 2017
UPTIME: 01:28:32
LOAD AVERAGE: 0.58, 0.42, 0.24
TASKS: 8
NODENAME: lenovo-thinkstation-01.lab.bos.redhat.com
RELEASE: 4.15.0-0.rc0.git6.1.fc28.x86_64
VERSION: #1 SMP Mon Nov 20 18:08:48 UTC 2017
MACHINE: x86_64 (2925 Mhz)
MEMORY: 4 GB
PID: 1687
COMMAND: "crash"
TASK: ffff9b1d2a903380 [THREAD_INFO: ffff9b1d2a903380]
CPU: 5
STATE: TASK_RUNNING (ACTIVE)
WARNING: only the active tasks on each cpu are being tracked
crash>
Dave