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

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Date:	Thu, 5 May 2016 10:37:58 +0800
From:	Baoquan He <bhe@...hat.com>
To:	Corey Minyard <minyard@....org>
Cc:	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Vivek Goyal <vgoyal@...hat.com>,
	Haren Myneni <hbabu@...ibm.com>,
	Corey Minyard <cminyard@...sta.com>, dyoung@...hat.com
Subject: Re: [PATCH] kdump: Fix gdb macros work work with newer and 64-bit
 kernels

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.

Vivek is busy with some other issues. He asked Dave and me to test and
review this patch. Will check this recently.

Thanks
Baoquan

> 
> -corey
> 
> On 02/25/2016 07:51 AM, minyard@....org wrote:
> >From: Corey Minyard <cminyard@...sta.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@...sta.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