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>
This commit is contained in:
Baruch Siach 2010-08-09 17:20:53 -07:00 коммит произвёл Linus Torvalds
Родитель 55817d3d5c
Коммит e3f76e3386
1 изменённых файлов: 6 добавлений и 0 удалений

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@ -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);