On 05/16/16 at 05:32pm, Baoquan He wrote:
> On 05/10/16 at 07:30pm, miny...@acm.org wrote:
> > From: Corey Minyard <cminy...@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 <cminy...@mvista.com>
> 
> Hi Corey,
> 
> Today I tried gdbmacro.txt and found dmesg doesn't work. I tested it
> on the latest 4.6.0 kernel. And I directly copy /proc/vmcore out
> and use gdb to open it by below command" 
> 
> gdb vmlinux /var/crash/vmcore --"gdbmacros.txt"
                Here I means  --command="gdbmacros.txt"

> 
> All macro functions work well except of dmesg since code inside refer to
> the deprecated variable like "log_end" and "logged_chars". But these
> have been changed since this commit:
> 
> commit 7ff9554bb578ba02166071d2d487b7fc7d860d62
> Author: Kay Sievers <k...@vrfy.org>
> Date:   Thu May 3 02:29:13 2012 +0200
> 
>     printk: convert byte-buffer to variable-length record buffer
> 
> So invoking dmesg will cause an error message printing out:
> 
> (gdb) dmesg
> No symbol "log_end" in current context.
> 
> Thanks
> Baoquan
> 
> > ---
> > 
> > Changes since v1:
> > 
> > Rename btthreadstruct to btthreadstack
> > 
> > Use sizeof(union thread_union) for the stack size instead of a hardcoded
> > 4096.
> > 
> >  Documentation/kdump/gdbmacros.txt | 96 
> > ++++++++++++++++++---------------------
> >  1 file changed, 44 insertions(+), 52 deletions(-)
> > 
> > diff --git a/Documentation/kdump/gdbmacros.txt 
> > b/Documentation/kdump/gdbmacros.txt
> > index 9b9b454..35f6a98 100644
> > --- a/Documentation/kdump/gdbmacros.txt
> > +++ b/Documentation/kdump/gdbmacros.txt
> > @@ -15,15 +15,16 @@
> >  
> >  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)
> > +   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.esp
> > -           set var $stack_top = ($stackp & ~4095) + 4096
> > +           set var $stackp = $next_t.thread.sp
> > +           set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
> >  
> >             while ($stackp < $stack_top)
> >                     if (*($stackp) > _stext && *($stackp) < _sinittext)
> > @@ -31,13 +32,13 @@ 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 $stack_top = ($stackp & ~4095) + 4096
> > +                   set var $stackp = $next_t.thread.sp
> > +                   set var $stack_top = ($stackp & ~($stacksize - 1)) + 
> > stacksize
> >  
> >                     while ($stackp < $stack_top)
> >                             if (*($stackp) > _stext && *($stackp) < 
> > _sinittext)
> > @@ -45,7 +46,7 @@ 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 +55,44 @@ 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)->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)
> > -
> > -           set $stackp = *($stackp)
> > -           while (($stackp < $stack_top) && ($stackp > $stack_bot))
> > -                   set var $addr = *($stackp + 4)
> > -                   info symbol $addr
> > -                   set $stackp = *($stackp)
> > -           end
> > +           btthreadstack $next_t
> >  
> > -           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)
> > +                   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
> > @@ -101,7 +104,7 @@ 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 +116,18 @@ 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
> > +   btthreadstack $pid_task
> >  end
> >  document btpid
> >     backtrace of pid
> > @@ -145,7 +137,7 @@ 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 +149,13 @@ 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
> > -- 
> > 2.7.4
> > 
> > 
> > _______________________________________________
> > kexec mailing list
> > ke...@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
> 
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