# # 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= option # # Credits: # Alexander Nyberg # V Srivatsa # Maneesh Soni # 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 ' 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