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

Started byBaoquan He <bhe@redhat.com>
First post2016-05-09 07:20 +0200
Last post2016-05-10 03:50 +0200
Articles 6 — 3 participants

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  Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Baoquan He <bhe@redhat.com> - 2016-05-09 07:20 +0200
    Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Corey Minyard <minyard@acm.org> - 2016-05-09 14:20 +0200
      Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Baoquan He <bhe@redhat.com> - 2016-05-09 16:40 +0200
        Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Corey Minyard <cminyard@mvista.com> - 2016-05-09 17:50 +0200
          Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Baoquan He <bhe@redhat.com> - 2016-05-10 03:40 +0200
      Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit  kernels Baoquan He <bhe@redhat.com> - 2016-05-10 03:50 +0200

#1396590 — Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit kernels

FromBaoquan He <bhe@redhat.com>
Date2016-05-09 07:20 +0200
SubjectRe: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit kernels
Message-ID<rwLLQ-64x-5@gated-at.bofh.it>
Hi Corey,

I am trying to review this patch now, and these fixes contained are very
great. Just several concerns are added in inline comment.

By the way, did you run this in your side?

Hi Vivek,

Member variable was added into task_struct in below commit replacing
pids[PIDTYPE_TGID], and from then on nobody complained about it. Seems
people rarely use this utility.

commit 47e65328a7b1cdfc4e3102e50d60faf94ebba7d3
Author: Oleg Nesterov <oleg@tv-sign.ru>
Date:   Tue Mar 28 16:11:25 2006 -0800

    [PATCH] pids: kill PIDTYPE_TGID



On 04/27/16 at 07:21am, Corey Minyard wrote:
> 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@acm.org wrote:
> >From: Corey Minyard <cminyard@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@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)

This is a quite nice fix.

> >  	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

This is a nice wrapping, but I guess you want to name it as
btthreadstack, right? Since I didn't get at all why it's related to
thread_struct except of getting 'sp'.

> >+	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

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#1396997

FromCorey Minyard <minyard@acm.org>
Date2016-05-09 14:20 +0200
Message-ID<rwSkh-5t9-1@gated-at.bofh.it>
In reply to#1396590
On 05/09/2016 12:18 AM, Baoquan He wrote:
> Hi Corey,
>
> I am trying to review this patch now, and these fixes contained are very
> great. Just several concerns are added in inline comment.
>
> By the way, did you run this in your side?

Yes, I tested on x86, x86_64, ARM and MIPS.

Comments inline...


> Hi Vivek,
>
> Member variable was added into task_struct in below commit replacing
> pids[PIDTYPE_TGID], and from then on nobody complained about it. Seems
> people rarely use this utility.
>
> commit 47e65328a7b1cdfc4e3102e50d60faf94ebba7d3
> Author: Oleg Nesterov <oleg@tv-sign.ru>
> Date:   Tue Mar 28 16:11:25 2006 -0800
>
>      [PATCH] pids: kill PIDTYPE_TGID
>
>
>
> On 04/27/16 at 07:21am, Corey Minyard wrote:
>> 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@acm.org wrote:
>>> From: Corey Minyard <cminyard@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@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)
> This is a quite nice fix.
>
>>>   	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
> This is a nice wrapping, but I guess you want to name it as
> btthreadstack, right? Since I didn't get at all why it's related to
> thread_struct except of getting 'sp'.
>

The name is based on what is passed into the function.  You do a 
backtrace when given a thread structure.  In my experience it is best to 
name functions based upon how the function's user sees it. Though I'm 
not stuck on the name, if you would prefer 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 $stack_top = ($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

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#1397099

FromBaoquan He <bhe@redhat.com>
Date2016-05-09 16:40 +0200
Message-ID<rwUvM-7tx-13@gated-at.bofh.it>
In reply to#1396997
On 05/09/16 at 07:10am, Corey Minyard wrote:
> On 05/09/2016 12:18 AM, Baoquan He wrote:
> >Hi Corey,
> >
> >I am trying to review this patch now, and these fixes contained are very
> >great. Just several concerns are added in inline comment.
> >
> >By the way, did you run this in your side?
> 
> Yes, I tested on x86, x86_64, ARM and MIPS.
> 
> Comments inline...

That's awesome. I will have a try too.

> >>>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)
> >This is a quite nice fix.
> >
> >>>  	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

Missed one place here. Currently the kernel stack is decided by
THREAD_SIZE since the definition:

union thread_union {
        struct thread_info thread_info;
        unsigned long stack[THREAD_SIZE/sizeof(long)];
};

Should we get the top and bottom of stack according to this now?

Correct me if I was wrong.

Thanks
Baoquan

> >>>  		while ($stackp < $stack_top)
> >>>@@ -31,12 +31,12 @@ define bttnobp
> >>>  			end
> >>>  			set $stackp += 4
> >>>  		end

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#1397152

FromCorey Minyard <cminyard@mvista.com>
Date2016-05-09 17:50 +0200
Message-ID<rwVBw-8t-11@gated-at.bofh.it>
In reply to#1397099
On 05/09/2016 09:29 AM, Baoquan He wrote:
> On 05/09/16 at 07:10am, Corey Minyard wrote:
>> On 05/09/2016 12:18 AM, Baoquan He wrote:
>>> Hi Corey,
>>>
>>> I am trying to review this patch now, and these fixes contained are very
>>> great. Just several concerns are added in inline comment.
>>>
>>> By the way, did you run this in your side?
>> Yes, I tested on x86, x86_64, ARM and MIPS.
>>
>> Comments inline...
> That's awesome. I will have a try too.
>
>>>>> 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)
>>> This is a quite nice fix.
>>>
>>>>>   	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
> Missed one place here. Currently the kernel stack is decided by
> THREAD_SIZE since the definition:
>
> union thread_union {
>          struct thread_info thread_info;
>          unsigned long stack[THREAD_SIZE/sizeof(long)];
> };
>
> Should we get the top and bottom of stack according to this now?
>
> Correct me if I was wrong.

I think you are correct.  We should use something like:

    set var $stack_top = ($stackp & ~(sizeof(thread_union) - 1)) +
    sizeof(thread_union)

Is this what you are suggesting?

-corey

>
> Thanks
> Baoquan
>
>>>>>   		while ($stackp < $stack_top)
>>>>> @@ -31,12 +31,12 @@ define bttnobp
>>>>>   			end
>>>>>   			set $stackp += 4
>>>>>   		end

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#1397629

FromBaoquan He <bhe@redhat.com>
Date2016-05-10 03:40 +0200
Message-ID<rx4Ou-K8-3@gated-at.bofh.it>
In reply to#1397152
On 05/09/16 at 10:40am, Corey Minyard wrote:
> >>>>>  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)
> >>>This is a quite nice fix.
> >>>
> >>>>>  	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
> >Missed one place here. Currently the kernel stack is decided by
> >THREAD_SIZE since the definition:
> >
> >union thread_union {
> >         struct thread_info thread_info;
> >         unsigned long stack[THREAD_SIZE/sizeof(long)];
> >};
> >
> >Should we get the top and bottom of stack according to this now?
> >
> >Correct me if I was wrong.
> 
> I think you are correct.  We should use something like:
> 
>    set var $stack_top = ($stackp & ~(sizeof(thread_union) - 1)) +
>    sizeof(thread_union)
> 
> Is this what you are suggesting?

Exactly, it's cool. Thanks!

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#1397636

FromBaoquan He <bhe@redhat.com>
Date2016-05-10 03:50 +0200
Message-ID<rx4Ya-OL-15@gated-at.bofh.it>
In reply to#1396997
Hi Corey,

On 05/09/16 at 07:10am, Corey Minyard wrote:
> >>>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
> >>>@@ -54,42 +54,43 @@ document bttnobp
> >>>  	dump all thread stack traces on a kernel compiled with !CONFIG_FRAME_POINTER
> >>>  end
> >>>+define btthreadstruct
> >This is a nice wrapping, but I guess you want to name it as
> >btthreadstack, right? Since I didn't get at all why it's related to
> >thread_struct except of getting 'sp'.
> >
> 
> The name is based on what is passed into the function.  You do a
> backtrace when given a thread structure.  In my experience it is
> best to name functions based upon how the function's user sees it.
> Though I'm not stuck on the name, if you would prefer btthreadstack.

About the name, in fact a task struct is passed in. Mainly there's a
thread_struct defined in x86 ARCH, I thought you are handling
thread_struct related things when I look at the first glance.
btthreadstack is far better name that that, I like it.

******************************
arch/x86/include/asm/processor.h
struct thread_struct {         
        /* Cached TLS descriptors: */   
        struct desc_struct      tls_array[GDT_ENTRY_TLS_ENTRIES];
        unsigned long           sp0;    
        unsigned long           sp;     
#ifdef CONFIG_X86_32           
        unsigned long           sysenter_cs;
#else
......
}

Thanks
Baoquan

> 
> >>>+	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

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