linux-ramdump-parser-v2: Check for loops in workqueues

Workqueues may be modified at runtime which can leave them in an
inconsistent state in ram dumps. Check for infinite loops in
workqueue lists caused by this state.

Change-Id: If5d8ebe48a538ffae58a8ed485cd4a50b20d60bf

linux-ramdump-parser-v2/parsers/workqueue.py

@@ -269,6 +269,7 @@ class Workqueues(RamParser):
                             break
 
             worker_pool = workqueue_i + pools_offset
+            seen = []
             # Need better way to ge the number of pools...
             for k in range(0, 2):
                 worker_pool_i = worker_pool + k * worker_pool_size
@@ -279,9 +280,11 @@ class Workqueues(RamParser):
                     worker_addr = next_entry - worker_entry_offset
                     worker_task_addr = ram_dump.read_word(
                         next_entry - worker_entry_offset + worker_task_offset)
-                    if worker_task_addr is None or worker_task_addr == 0:
+                    if worker_task_addr is None or worker_task_addr == 0 or worker_task_addr in seen:
                         break
 
+                    seen.append(worker_task_addr)
+
                     taskname = ram_dump.read_cstring(
                         (worker_task_addr + offset_comm), 16)
                     scheduled_addr = ram_dump.read_word(
@@ -420,13 +423,16 @@ class Workqueues(RamParser):
 
                 idle_list_addr = worker_pool_i + pool_idle_offset
                 next_entry = ram_dump.read_word(idle_list_addr)
+                seen = []
                 while True:
                     worker_addr = next_entry - worker_entry_offset
                     worker_task_addr = ram_dump.read_word(
                         next_entry - worker_entry_offset + worker_task_offset)
-                    if worker_task_addr is None or worker_task_addr == 0:
+                    if worker_task_addr is None or worker_task_addr == 0 or worker_task_addr in seen:
                         break
 
+                    seen.append(worker_task_addr)
+
                     taskname = ram_dump.read_cstring(
                         (worker_task_addr + offset_comm), 16)
                     scheduled_addr = ram_dump.read_word(