Re: [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals

["Andreas Färber" <afaerber@suse.de>]

Tim,

Am 14.10.2012 15:08, schrieb Tim Hardeck:
> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list
> QEMU segfaults.

Can this be reproduced by a user today? Or is this just fixing the case
that a developer forgot to initialize a list?

Regards,
Andreas

> Check for this case specifically on item removal.
> 
> Signed-off-by: Tim Hardeck <thardeck@suse.de>
> ---
>  qemu-queue.h |    8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/qemu-queue.h b/qemu-queue.h
> index 9288cd8..47ed239 100644
> --- a/qemu-queue.h
> +++ b/qemu-queue.h
> @@ -141,7 +141,9 @@ struct {                                                                \
>          if ((elm)->field.le_next != NULL)                               \
>                  (elm)->field.le_next->field.le_prev =                   \
>                      (elm)->field.le_prev;                               \
> -        *(elm)->field.le_prev = (elm)->field.le_next;                   \
> +        if ((elm)->field.le_prev != NULL) {                             \
> +            *(elm)->field.le_prev = (elm)->field.le_next;               \
> +        }                                                               \
>  } while (/*CONSTCOND*/0)
>  
>  #define QLIST_FOREACH(var, head, field)                                 \
> @@ -381,7 +383,9 @@ struct {                                                                \
>                      (elm)->field.tqe_prev;                              \
>          else                                                            \
>                  (head)->tqh_last = (elm)->field.tqe_prev;               \
> -        *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
> +        if ((elm)->field.tqe_prev != NULL) {                            \
> +            *(elm)->field.tqe_prev = (elm)->field.tqe_next;             \
> +        }                                                               \
>  } while (/*CONSTCOND*/0)
>  
>  #define QTAILQ_FOREACH(var, head, field)                                \


-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg