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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 dump_log_idx
+ set $idx = $arg0
+ if ($argc > 1)
+ set $prev_flags = $arg1
+ else
+ set $prev_flags = 0
+ end
+ set $msg = ((struct printk_log *) (log_buf + $idx))
+ set $prefix = 1
+ set $newline = 1
+ set $log = log_buf + $idx + sizeof(*$msg)
+
+ # prev & LOG_CONT && !(msg->flags & LOG_PREIX)
+ if (($prev_flags & 8) && !($msg->flags & 4))
+ set $prefix = 0
+ end
+
+ # msg->flags & LOG_CONT
+ if ($msg->flags & 8)
+ # (prev & LOG_CONT && !(prev & LOG_NEWLINE))
+ if (($prev_flags & 8) && !($prev_flags & 2))
+ set $prefix = 0
+ end
+ # (!(msg->flags & LOG_NEWLINE))
+ if (!($msg->flags & 2))
+ set $newline = 0
+ end
+ end
+
+ if ($prefix)
+ printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000
+ end
+ if ($msg->text_len != 0)
+ eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len
+ end
+ if ($newline)
+ printf "\n"
+ end
+ if ($msg->dict_len > 0)
+ set $dict = $log + $msg->text_len
+ set $idx = 0
+ set $line = 1
+ while ($idx < $msg->dict_len)
+ if ($line)
+ printf " "
+ set $line = 0
+ end
+ set $c = $dict[$idx]
+ if ($c == '\0')
+ printf "\n"
+ set $line = 1
+ else
+ if ($c < ' ' || $c >= 127 || $c == '\\')
+ printf "\\x%02x", $c
+ else
+ printf "%c", $c
+ end
+ end
+ set $idx = $idx + 1
+ end
+ printf "\n"
+ end
+end
+document dump_log_idx
+ Dump a single log given its index in the log buffer. The first
+ parameter is the index into log_buf, the second is optional and
+ specified the previous log buffer's flags, used for properly
+ formatting continued lines.
+end
+
+define dmesg
+ set $i = log_first_idx
+ set $end_idx = log_first_idx
+ set $prev_flags = 0
+
+ while (1)
+ set $msg = ((struct printk_log *) (log_buf + $i))
+ if ($msg->len == 0)
+ set $i = 0
+ else
+ dump_log_idx $i $prev_flags
+ set $i = $i + $msg->len
+ set $prev_flags = $msg->flags
+ end
+ if ($i == $end_idx)
+ loop_break
+ end
+ end
+end
+document dmesg
+ print the kernel ring buffer
+end