Re: [PATCH v2] kdump: Fix gdb macros work work with newer and 64-bit kernels
From: Corey Minyard
Date: Mon May 16 2016 - 07:52:34 EST
On 05/16/2016 04:32 AM, Baoquan He wrote:
On 05/10/16 at 07:30pm, minyard@xxxxxxx wrote:
From: Corey Minyard <cminyard@xxxxxxxxxx>
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@xxxxxxxxxx>
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@xxxxxxxx>
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
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