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

Message ID 1456408291-29559-1-git-send-email-minyard@acm.org
State New
Headers show

Commit Message

Corey Minyard Feb. 25, 2016, 1:51 p.m. UTC 
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.

-- 
2.5.0

Comments

Corey Minyard May 9, 2016, 3:40 p.m. UTC | #1 
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
diff mbox

Patch

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