[PATCH] kdump: Fix gdb macros work work with newer and 64-bit kernels

[Corey Minyard]

Any comments on this?  If no one else cares I'd be willing to take over
maintenance of this.

-corey

On 02/25/2016 07:51 AM, minyard at acm.org wrote:
> From: Corey Minyard <cminyard at mvista.com>
>
> Lots of little changes needed to be made to clean these up, remove the
> four byte pointer assumption and traverse the pid queue properly.
> Also consolidate the traceback code into a single function instead
> of having three copies of it.
>
> Signed-off-by: Corey Minyard <cminyard at mvista.com>
> ---
>   Documentation/kdump/gdbmacros.txt | 90 +++++++++++++++++----------------------
>   1 file changed, 40 insertions(+), 50 deletions(-)
>
> I sent this earlier, but I didn't get a response.  These are clearly
> wrong.  I'd be happy to take over maintenance of these macros.  It
> might be better to move them someplace else, too, since they are also
> useful for kgdb.
>
> diff --git a/Documentation/kdump/gdbmacros.txt b/Documentation/kdump/gdbmacros.txt
> index 9b9b454..e5bbd8d 100644
> --- a/Documentation/kdump/gdbmacros.txt
> +++ b/Documentation/kdump/gdbmacros.txt
> @@ -15,14 +15,14 @@
>   
>   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 $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
>   		printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
>   		printf "===================\n"
> -		set var $stackp = $next_t.thread.esp
> +		set var $stackp = $next_t.thread.sp
>   		set var $stack_top = ($stackp & ~4095) + 4096
>   
>   		while ($stackp < $stack_top)
> @@ -31,12 +31,12 @@ define bttnobp
>   			end
>   			set $stackp += 4
>   		end
> -		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
> +		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.esp
> +			set var $stackp = $next_t.thread.sp
>   			set var $stack_top = ($stackp & ~4095) + 4096
>   
>   			while ($stackp < $stack_top)
> @@ -45,7 +45,7 @@ define bttnobp
>   				end
>   				set $stackp += 4
>   			end
> -			set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
> +			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
>   		end
>   		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
>   	end
> @@ -54,42 +54,43 @@ document bttnobp
>   	dump all thread stack traces on a kernel compiled with !CONFIG_FRAME_POINTER
>   end
>   
> +define btthreadstruct
> +	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 $stack_top = ($stackp & ~4095) + 4096
> +	set var $stack_bot = ($stackp & ~4095)
> +
> +	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 btthreadstruct
> +	 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)->pids[1].pid_list.next)
> +	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
> -		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)
> +		btthreadstruct $next_t
>   
> -		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)
> +		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.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)
> +			btthreadstruct $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
> @@ -101,7 +102,7 @@ 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 $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
> @@ -113,29 +114,18 @@ define btpid
>   			set $pid_task = $next_t
>   		end
>   
> -		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
> +		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->pids[1].pid_list.next) - $pid_off)
> +			set $next_th=(((char *)$next_th->thread_group.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
> +	btthreadstruct $pid_task
>   end
>   document btpid
>   	backtrace of pid
> @@ -145,7 +135,7 @@ 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 $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
> @@ -157,13 +147,13 @@ define trapinfo
>   			set $pid_task = $next_t
>   		end
>   
> -		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
> +		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->pids[1].pid_list.next) - $pid_off)
> +			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
>   		end
>   		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
>   	end