[PATCH v2] kdump: Fix gdb macros work work with newer and 64-bit kernels
Corey Minyard
minyard at acm.org
Mon May 16 04:52:24 PDT 2016
On 05/16/2016 04:32 AM, Baoquan He wrote:
> On 05/10/16 at 07:30pm, 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>
> 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"
>
> 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 <kay at 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.
Yes, I was actually aware of that, but that's a different issue and I
hadn't thought about it much.
-corey
> 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
>> kexec at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
More information about the kexec
mailing list