Linux Cross Reference
Linux-2.6.17/Documentation/kdump/gdbmacros.txt

   #
   # 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
 
 
 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