OpenCloudOS-Kernel/Documentation/kdump/gdbmacros.txt

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#
# 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)->thread_group.next)
set $init_t=&init_task
set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
set var $stacksize = sizeof(union thread_union)
while ($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.sp
set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
while ($stackp < $stack_top)
if (*($stackp) > _stext && *($stackp) < _sinittext)
info symbol *($stackp)
end
set $stackp += 4
end
set $next_th=(((char *)$next_t->thread_group.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.sp
set var $stack_top = ($stackp & ~($stacksize - 1)) + stacksize
while ($stackp < $stack_top)
if (*($stackp) > _stext && *($stackp) < _sinittext)
info symbol *($stackp)
end
set $stackp += 4
end
set $next_th=(((char *)$next_th->thread_group.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 btthreadstack
set var $pid_task = $arg0
printf "\npid %d; comm %s:\n", $pid_task.pid, $pid_task.comm
printf "task struct: "
print $pid_task
printf "===================\n"
set var $stackp = $pid_task.thread.sp
set var $stacksize = sizeof(union thread_union)
set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
set var $stack_bot = ($stackp & ~($stacksize - 1))
set $stackp = *((unsigned long *) $stackp)
while (($stackp < $stack_top) && ($stackp > $stack_bot))
set var $addr = *(((unsigned long *) $stackp) + 1)
info symbol $addr
set $stackp = *((unsigned long *) $stackp)
end
end
document btthreadstack
dump a thread stack using the given task structure pointer
end
define btt
set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.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
btthreadstack $next_t
set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
while ($next_th != $next_t)
set $next_th=(struct task_struct *)$next_th
btthreadstack $next_th
set $next_th=(((char *)$next_th->thread_group.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)->thread_group.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->thread_group.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->thread_group.next) - $pid_off)
end
set $next_t=(char *)($next_t->tasks.next) - $tasks_off
end
btthreadstack $pid_task
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)->thread_group.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->thread_group.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->thread_group.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
address the kernel panicked.
end
define dmesg
set $i = 0
set $end_idx = (log_end - 1) & (log_buf_len - 1)
while ($i < logged_chars)
set $idx = (log_end - 1 - logged_chars + $i) & (log_buf_len - 1)
if ($idx + 100 <= $end_idx) || \
($end_idx <= $idx && $idx + 100 < log_buf_len)
printf "%.100s", &log_buf[$idx]
set $i = $i + 100
else
printf "%c", log_buf[$idx]
set $i = $i + 1
end
end
end
document dmesg
print the kernel ring buffer
end