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Commit e3f76e33 authored by Baruch Siach's avatar Baruch Siach Committed by Linus Torvalds
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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: default avatarBaruch Siach <baruch@tkos.co.il>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 55817d3d

lib/list_debug.c

+6 −0
Original line number Diff line number Diff line
@@ -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);