======================================================================== * README ======================================================================== CORE ANALYSIS SUITE The core analysis suite is a self-contained tool that can be used to investigate either live systems, kernel core dumps created from the netdump and diskdump packages offered by Red Hat, the LKCD kernel patch or the mcore kernel patch available from Mission Critical Linux. o The tool is loosely based on the SVR4 crash command, but has been completely integrated with gdb in order to be able to display formatted kernel data structures, disassemble source code, etc. o The current set of available commands consist of common kernel core analysis tools such as a context-specific stack traces, source code disassembly, kernel variable displays, memory display, dumps of linked-lists, etc. In addition, any gdb command may be entered, which in turn will be passed onto the gdb module for execution. o There are several commands that delve deeper into specific kernel subsystems, which also serve as templates for kernel developers to create new commands for analysis of a specific area of interest. Adding a new command is a simple affair, and a quick recompile adds it to the command menu. o The intent is to make the tool independent of Linux version dependencies, building in recognition of major kernel code changes so as to adapt to new kernel versions, while maintaining backwards compatibility. A whitepaper with complete documentation concerning the use of this utility can be found here: http://people.redhat.com/anderson/crash_whitepaper These are the current prerequisites: o At this point, x86, ia64, x86_64, ppc64, alpha, s390 and s390x-based kernels are supported. Other architectures may be addressed in the future. o One size fits all -- the utility can be run on any Linux kernel version from 2.2.5-15 through 2.6.*. o In order to contain debugging data, the top-level kernel Makefile's CFLAGS definition must contain the -g flag. If not, the kernel must be rebuilt. For 2.2 kernels that are not built with -g, change the following line: CFLAGS = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer to: CFLAGS = -g -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer For 2.4 kernels that are not built with -g, change the following line: CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -fno-strict-aliasing to: CFLAGS := -g $(CPPFLAGS) -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -fno-strict-aliasing For 2.6 kernels that are not built with -g, change the following line: CFLAGS := -Wall -Wstrict-prototypes -Wno-trigraphs \ to: CFLAGS := -g -Wall -Wstrict-prototypes -Wno-trigraphs \ After the kernel is re-compiled, the uncompressed "vmlinux" kernel that is created in the top-level kernel build directory must be saved. To build this utility, simply uncompress the tar file, enter the crash-4.0 subdirectory, and type "make". The initial build will take several minutes because the gdb module must be configured and and built. Alternatively, the crash source RPM file may be installed and built, and the resultant crash binary RPM file installed. If the tool is run against a crash dumpfile, two arguments are required, the uncompressed kernel name and the core dumpfile name. If run on a live system, only the kernel name is required, because /dev/mem will be used as the "dumpfile". If the kernel file is stored in /boot, /, /boot/efi, or in any /usr/src subdirectory, then no command line arguments are required -- the first kernel found that matches /proc/version will be used as the namelist. For example, if the command name "crash" is kept intact in the Makefile, invoking it on a live system would look like this: $ crash crash 4.0 Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. Copyright (C) 2004, 2005 IBM Corporation Copyright (C) 1999-2005 Hewlett-Packard Co 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 2003 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 "i686-pc-linux-gnu".. KERNEL: /boot/vmlinux DUMPFILE: /dev/mem CPUS: 1 DATE: Wed Jul 13 13:26:00 2005 UPTIME: 10 days, 22:55:18 LOAD AVERAGE: 0.08, 0.03, 0.01 TASKS: 42 NODENAME: ha2.mclinux.com RELEASE: 2.4.0-test10 VERSION: #11 SMP Thu Nov 4 15:09:25 EST 2000 MACHINE: i686 (447 MHz) MEMORY: 128 MB PID: 3621 COMMAND: "crash" TASK: c463c000 CPU: 0 STATE: TASK_RUNNING (ACTIVE) crash> help * files mod runq union alias foreach mount search vm ascii fuser net set vtop bt gdb p sig waitq btop help ps struct whatis dev irq pte swap wr dis kmem ptob sym q eval list ptov sys exit log rd task extend mach repeat timer crash version: 4.0 gdb version: 6.1 For help on any command above, enter "help ". For help on input options, enter "help input". For help on output options, enter "help output". crash> When run on a dumpfile, both the kernel namelist and dumpfile must be entered on the command line. For example, when run on a core dump created by the Red Hat netdump or diskdump facilities: $ crash vmlinux vmcore crash 4.0 Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. Copyright (C) 2004, 2005 IBM Corporation Copyright (C) 1999-2005 Hewlett-Packard Co 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 2003 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 "i686-pc-linux-gnu"... KERNEL: vmlinux DUMPFILE: vmcore CPUS: 4 DATE: Tue Mar 2 13:57:09 2004 UPTIME: 00:02:40 LOAD AVERAGE: 2.24, 0.96, 0.37 TASKS: 70 NODENAME: pro1.lab.boston.redhat.com RELEASE: 2.6.3-2.1.214.11smp VERSION: #1 SMP Tue Mar 2 10:58:27 EST 2004 MACHINE: i686 (2785 Mhz) MEMORY: 512 MB PANIC: "Oops: 0002 [#1]" (check log for details) PID: 0 COMMAND: "swapper" TASK: 22fa200 (1 of 4) [THREAD_INFO: 2356000] CPU: 0 STATE: TASK_RUNNING (PANIC) crash> When run on a core dump created by the MCLX mcore patch: $ crash vmlinux.17 lcore.cr.17 crash 4.0 Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. Copyright (C) 2004, 2005 IBM Corporation Copyright (C) 1999-2005 Hewlett-Packard Co 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 2003 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 "i686-pc-linux-gnu"... KERNEL: vmlinux.17 DUMPFILE: lcore.cr.17 CPUS: 1 DATE: Wed Nov 10 19:54:47 1999 UPTIME: 00:02:02 LOAD AVERAGE: 0.82, 0.34, 0.12 TASKS: 43 NODENAME: ha3.mclinux.com RELEASE: 2.2.5-15 VERSION: #39 Wed Nov 10 17:43:16 CST 1999 MACHINE: i686 (501 MHz) MEMORY: 96 MB PANIC: "tulip_interrupt" PID: 286 COMMAND: "in.rlogind" TASK: c0b3a000 CPU: 0 STATE: TASK_RUNNING (PANIC) crash> When run on an LKCD core dump, the command line would be like so: $ crash vmlinux vmdump.0 The tool's environment is context-specific. On a live system, the default context is the command itself; on a dump the default context will be the task that panicked. The most commonly-used commands are: set - set a new task context by pid, task address, or cpu. bt - backtrace of the current context, or as specified with arguments. p - print the contents of a kernel variable. rd - read memory, which may be either kernel virtual, user virtual, or physical. ps - simple process listing. log - dump the kernel log_buf. struct - print the contents of a structure at a specified address. foreach - execute a command on all tasks, or those specified, in the system. Detailed help concerning the use of each of the commands in the menu above may be displayed by entering "help command", where "command" is one of those listed above. Rather than getting bogged down in details here, simply run the help command on each of the commands above. Note that many commands have multiple options so as to avoid the proliferation of command names. Command output may be piped to external commands or redirected to files. Enter "help output" for details. The command line history mechanism allows for command-line recall and command-line editing. Input files containing a set of crash commands may be substituted for command-line input. Enter "help input" for details. Note that a .crashrc file (or .rc if the name has been changed), may contain any number of "set" or "alias" commands -- see the help pages on those two commands for details. Lastly, if a command is entered that is not recognized, it is checked against the kernel's list of variables, structure, union or typedef names, and if found, the command is passed to "p", "struct", "union" or "whatis". That being the case, as long as a kernel variable/structure/union name is different than any of the current commands. (1) A kernel variable can be dumped by simply entering its name: crash> init_mm init_mm = $2 = { mmap = 0xc022d540, mmap_avl = 0x0, mmap_cache = 0x0, pgd = 0xc0101000, count = { counter = 0x6 }, map_count = 0x1, mmap_sem = { count = { counter = 0x1 }, waking = 0x0, wait = 0x0 }, context = 0x0, start_code = 0xc0000000, end_code = 0xc022b4c8, end_data = c0250388, ... (2) A structure or can be dumped simply by entering its name and address: crash> vm_area_struct c5ba3910 struct vm_area_struct { vm_mm = 0xc3ae3210, vm_start = 0x821b000, vm_end = 0x8692000, vm_next = 0xc5ba3890, vm_page_prot = { pgprot = 0x25 }, vm_flags = 0x77, vm_avl_height = 0x4, vm_avl_left = 0xc0499540, vm_avl_right = 0xc0499f40, vm_next_share = 0xc04993c0, vm_pprev_share = 0xc0499060, vm_ops = 0x0, vm_offset = 0x0, vm_file = 0x0, vm_pte = 0x0 } The crash utility has been designed to facilitate the task of adding new commands. New commands may be permanently compiled into the crash executable, or dynamically added during runtime using shared object files. To permanently add a new command to the crash executable's menu: 1. For a command named "xxx", put a reference to cmd_xxx() in defs.h. 2. Add cmd_xxx into the base_command_table[] array in global_data.c. 3. Write cmd_xxx(), putting it in one of the appropriate files. Look at the other commands for guidance on getting symbolic data, reading memory, displaying data, etc... 4. Recompile and run. Note that while the initial compile of crash, which configures and compiles the gdb module, takes several minutes, subsequent re-compiles to do such things as add new commands or fix bugs just takes a few seconds. Alternatively, you can create shared object library files consisting of crash command extensions, that can be dynamically linked into the crash executable during runtime or during initialization. This will allow the the same shared object to be used with subsequent crash releases without having to re-merge the command's code into each new set of crash sources. The dynamically linked-in commands will automatically show up in the crash help menu. For details, enter "help extend" during runtime, or enter "crash -h extend" from the shell command line. ======================================================================== * COPYING ======================================================================== GNU GENERAL PUBLIC LICENSE Version 2, June 1991 Copyright (C) 1989, 1991 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The licenses for most software are designed to take away your freedom to share and change it. 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The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you". Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does. 1. 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If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License. 9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. 10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 12. 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It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. Copyright (C) 19yy This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Also add information on how to contact you by electronic and paper mail. If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) 19yy name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (which makes passes at compilers) written by James Hacker. , 1 April 1989 Ty Coon, President of Vice This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.