From e3f76e3386ee38e3654e81c2f3933ccca1f2d639 Mon Sep 17 00:00:00 2001
From: Baruch Siach <baruch@tkos.co.il>
Date: Mon, 9 Aug 2010 17:20:53 -0700
Subject: [PATCH] list debugging: warn when deleting a deleted entry
Use the magic LIST_POISON* values to detect an incorrect use of list_del
on a deleted entry. This DEBUG_LIST specific warning is easier to
understand than the generic Oops message caused by LIST_POISON
dereference.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/list_debug.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/list_debug.c b/lib/list_debug.c
index 1a39f4e3ae1f..344c710d16ca 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -43,6 +43,12 @@ EXPORT_SYMBOL(__list_add);
*/
void list_del(struct list_head *entry)
{
+ WARN(entry->next == LIST_POISON1,
+ "list_del corruption, next is LIST_POISON1 (%p)\n",
+ LIST_POISON1);
+ WARN(entry->next != LIST_POISON1 && entry->prev == LIST_POISON2,
+ "list_del corruption, prev is LIST_POISON2 (%p)\n",
+ LIST_POISON2);
WARN(entry->prev->next != entry,
"list_del corruption. prev->next should be %p, "
"but was %p\n", entry, entry->prev->next);
--
GitLab