kasan: print workqueue stack

The aux_stack[2] is reused to record the call_rcu() call stack and
enqueuing work call stacks.  So that we need to change the auxiliary stack
title for common title, print them in KASAN report.

Link: https://lkml.kernel.org/r/20201203022715.30635-1-walter-zh.wu@mediatek.comSigned-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Marco Elver <elver@google.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kasan/generic.c

@@ -339,9 +339,6 @@ void kasan_record_aux_stack(void *addr)
 	object = nearest_obj(cache, page, addr);
 	alloc_info = get_alloc_info(cache, object);
 
-	/*
-	 * record the last two call_rcu() call stacks.
-	 */
 	alloc_info->aux_stack[1] = alloc_info->aux_stack[0];
 	alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
 }

mm/kasan/report.c

@@ -185,12 +185,12 @@ static void describe_object(struct kmem_cache *cache, void *object,
 
 #ifdef CONFIG_KASAN_GENERIC
 		if (alloc_info->aux_stack[0]) {
-			pr_err("Last call_rcu():\n");
+			pr_err("Last potentially related work creation:\n");
 			print_stack(alloc_info->aux_stack[0]);
 			pr_err("\n");
 		}
 		if (alloc_info->aux_stack[1]) {
-			pr_err("Second to last call_rcu():\n");
+			pr_err("Second to last potentially related work creation:\n");
 			print_stack(alloc_info->aux_stack[1]);
 			pr_err("\n");
 		}