Re: [PATCH] list debugging: warn when deleting a deleted entry

From: Baruch Siach
Date: Sun May 16 2010 - 01:46:44 EST


Hi Dave,

Ping?
Any comment on this?

baruch

On Wed, May 05, 2010 at 11:14:29AM +0300, Baruch Siach wrote:
> 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@xxxxxxxxxx>
> ---
> lib/list_debug.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/lib/list_debug.c b/lib/list_debug.c
> index 1a39f4e..344c710 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);
> --
> 1.7.0
>

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