mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 09:59:32 +00:00
![Vivek Goyal](/assets/img/avatar_default.png)
This patch contains the documentation for the kexec based crash dump tool. Quick kdump-howto ================================================================ 1) Download and build kexec-tools. 2) Download and build the latest kexec/kdump (-mm) kernel patchset. Two kernels need to be built in order to get this feature working. A) First kernel: a) Enable "kexec system call" feature: CONFIG_KEXEC=y b) Physical load address (use default): CONFIG_PHYSICAL_START=0x100000 c) Enable "sysfs file system support": CONFIG_SYSFS=y d) Boot into first kernel with the command line parameter "crashkernel=Y@X": For example: "crashkernel=64M@16M". B) Second kernel: a) Enable "kernel crash dumps" feature: CONFIG_CRASH_DUMP=y b) Physical load addreess, use same load address as X in "crashkernel" kernel parameter in d) above, e.g., 16 MB or 0x1000000. CONFIG_PHYSICAL_START=0x1000000 c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems). CONFIG_PROC_VMCORE=y 3) Boot into the first kernel. 4) Load the second kernel to be booted using: kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev> maxcpus=1 init 1" 5) System reboots into the second kernel when a panic occurs. A module can be written to force the panic, for testing purposes. 6) See Documentation/kdump.txt for how to read the first kernel's memory image and how to analyze it. Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com> Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: randy_dunlap <rdunlap@xenotime.net> Signed-off-by: Maneesh Soni <maneesh@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
179 lines
5.5 KiB
Text
179 lines
5.5 KiB
Text
#
|
|
# This file contains a few gdb macros (user defined commands) to extract
|
|
# useful information from kernel crashdump (kdump) like stack traces of
|
|
# all the processes or a particular process and trapinfo.
|
|
#
|
|
# These macros can be used by copying this file in .gdbinit (put in home
|
|
# directory or current directory) or by invoking gdb command with
|
|
# --command=<command-file-name> option
|
|
#
|
|
# Credits:
|
|
# Alexander Nyberg <alexn@telia.com>
|
|
# V Srivatsa <vatsa@in.ibm.com>
|
|
# Maneesh Soni <maneesh@in.ibm.com>
|
|
#
|
|
|
|
define bttnobp
|
|
set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
|
|
set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
|
|
set $init_t=&init_task
|
|
set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
|
|
while ($next_t != $init_t)
|
|
set $next_t=(struct task_struct *)$next_t
|
|
printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
|
|
printf "===================\n"
|
|
set var $stackp = $next_t.thread.esp
|
|
set var $stack_top = ($stackp & ~4095) + 4096
|
|
|
|
while ($stackp < $stack_top)
|
|
if (*($stackp) > _stext && *($stackp) < _sinittext)
|
|
info symbol *($stackp)
|
|
end
|
|
set $stackp += 4
|
|
end
|
|
set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
|
|
while ($next_th != $next_t)
|
|
set $next_th=(struct task_struct *)$next_th
|
|
printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
|
|
printf "===================\n"
|
|
set var $stackp = $next_t.thread.esp
|
|
set var $stack_top = ($stackp & ~4095) + 4096
|
|
|
|
while ($stackp < $stack_top)
|
|
if (*($stackp) > _stext && *($stackp) < _sinittext)
|
|
info symbol *($stackp)
|
|
end
|
|
set $stackp += 4
|
|
end
|
|
set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
|
|
end
|
|
set $next_t=(char *)($next_t->tasks.next) - $tasks_off
|
|
end
|
|
end
|
|
document bttnobp
|
|
dump all thread stack traces on a kernel compiled with !CONFIG_FRAME_POINTER
|
|
end
|
|
|
|
define btt
|
|
set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
|
|
set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
|
|
set $init_t=&init_task
|
|
set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
|
|
while ($next_t != $init_t)
|
|
set $next_t=(struct task_struct *)$next_t
|
|
printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
|
|
printf "===================\n"
|
|
set var $stackp = $next_t.thread.esp
|
|
set var $stack_top = ($stackp & ~4095) + 4096
|
|
set var $stack_bot = ($stackp & ~4095)
|
|
|
|
set $stackp = *($stackp)
|
|
while (($stackp < $stack_top) && ($stackp > $stack_bot))
|
|
set var $addr = *($stackp + 4)
|
|
info symbol $addr
|
|
set $stackp = *($stackp)
|
|
end
|
|
|
|
set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
|
|
while ($next_th != $next_t)
|
|
set $next_th=(struct task_struct *)$next_th
|
|
printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
|
|
printf "===================\n"
|
|
set var $stackp = $next_t.thread.esp
|
|
set var $stack_top = ($stackp & ~4095) + 4096
|
|
set var $stack_bot = ($stackp & ~4095)
|
|
|
|
set $stackp = *($stackp)
|
|
while (($stackp < $stack_top) && ($stackp > $stack_bot))
|
|
set var $addr = *($stackp + 4)
|
|
info symbol $addr
|
|
set $stackp = *($stackp)
|
|
end
|
|
set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
|
|
end
|
|
set $next_t=(char *)($next_t->tasks.next) - $tasks_off
|
|
end
|
|
end
|
|
document btt
|
|
dump all thread stack traces on a kernel compiled with CONFIG_FRAME_POINTER
|
|
end
|
|
|
|
define btpid
|
|
set var $pid = $arg0
|
|
set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
|
|
set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
|
|
set $init_t=&init_task
|
|
set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
|
|
set var $pid_task = 0
|
|
|
|
while ($next_t != $init_t)
|
|
set $next_t=(struct task_struct *)$next_t
|
|
|
|
if ($next_t.pid == $pid)
|
|
set $pid_task = $next_t
|
|
end
|
|
|
|
set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
|
|
while ($next_th != $next_t)
|
|
set $next_th=(struct task_struct *)$next_th
|
|
if ($next_th.pid == $pid)
|
|
set $pid_task = $next_th
|
|
end
|
|
set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
|
|
end
|
|
set $next_t=(char *)($next_t->tasks.next) - $tasks_off
|
|
end
|
|
|
|
printf "\npid %d; comm %s:\n", $pid_task.pid, $pid_task.comm
|
|
printf "===================\n"
|
|
set var $stackp = $pid_task.thread.esp
|
|
set var $stack_top = ($stackp & ~4095) + 4096
|
|
set var $stack_bot = ($stackp & ~4095)
|
|
|
|
set $stackp = *($stackp)
|
|
while (($stackp < $stack_top) && ($stackp > $stack_bot))
|
|
set var $addr = *($stackp + 4)
|
|
info symbol $addr
|
|
set $stackp = *($stackp)
|
|
end
|
|
end
|
|
document btpid
|
|
backtrace of pid
|
|
end
|
|
|
|
|
|
define trapinfo
|
|
set var $pid = $arg0
|
|
set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
|
|
set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
|
|
set $init_t=&init_task
|
|
set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
|
|
set var $pid_task = 0
|
|
|
|
while ($next_t != $init_t)
|
|
set $next_t=(struct task_struct *)$next_t
|
|
|
|
if ($next_t.pid == $pid)
|
|
set $pid_task = $next_t
|
|
end
|
|
|
|
set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
|
|
while ($next_th != $next_t)
|
|
set $next_th=(struct task_struct *)$next_th
|
|
if ($next_th.pid == $pid)
|
|
set $pid_task = $next_th
|
|
end
|
|
set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
|
|
end
|
|
set $next_t=(char *)($next_t->tasks.next) - $tasks_off
|
|
end
|
|
|
|
printf "Trapno %ld, cr2 0x%lx, error_code %ld\n", $pid_task.thread.trap_no, \
|
|
$pid_task.thread.cr2, $pid_task.thread.error_code
|
|
|
|
end
|
|
document trapinfo
|
|
Run info threads and lookup pid of thread #1
|
|
'trapinfo <pid>' will tell you by which trap & possibly
|
|
addresthe kernel paniced.
|
|
end
|