[PATCH v2 1/3] scripts/gdb/tasks: Fix lx-ps command error

[Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>]

Since commit 8e1f385104ac ("kill task_struct->thread_group") remove
the thread_group, we will encounter below issue.

(gdb) lx-ps
      TASK          PID    COMM
0xffff800086503340   0   swapper/0
Python Exception <class 'gdb.error'>: There is no member named thread_group.
Error occurred in Python: There is no member named thread_group.

We use signal->thread_head to iterate all threads instead.

Fixes: 8e1f385104ac ("kill task_struct->thread_group")
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
---
 scripts/gdb/linux/tasks.py | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/scripts/gdb/linux/tasks.py b/scripts/gdb/linux/tasks.py
index 17ec19e9b5bf..aa5ab6251f76 100644
--- a/scripts/gdb/linux/tasks.py
+++ b/scripts/gdb/linux/tasks.py
@@ -13,7 +13,7 @@
 
 import gdb
 
-from linux import utils
+from linux import utils, lists
 
 
 task_type = utils.CachedType("struct task_struct")
@@ -22,19 +22,15 @@ task_type = utils.CachedType("struct task_struct")
 def task_lists():
     task_ptr_type = task_type.get_type().pointer()
     init_task = gdb.parse_and_eval("init_task").address
-    t = g = init_task
+    t = init_task
 
     while True:
-        while True:
-            yield t
+        thread_head = t['signal']['thread_head']
+        for thread in lists.list_for_each_entry(thread_head, task_ptr_type, 'thread_node'):
+            yield thread
 
-            t = utils.container_of(t['thread_group']['next'],
-                                   task_ptr_type, "thread_group")
-            if t == g:
-                break
-
-        t = g = utils.container_of(g['tasks']['next'],
-                                   task_ptr_type, "tasks")
+        t = utils.container_of(t['tasks']['next'],
+                               task_ptr_type, "tasks")
         if t == init_task:
             return
 
-- 
2.18.0