Re: [Qemu-devel] [PATCH 2/3] blockdev: Fix NULL pointer dereference in blockdev-add

["Benoît Canet" <benoit.canet@irqsave.net>]

The Thursday 06 Mar 2014 à 16:44:28 (+0100), Kevin Wolf wrote :
> If aio=native, we check that cache.direct is set as well. If however
> cache wasn't specified at all, qemu just segfaulted.
> 
> The old condition didn't make any sense anyway because it effectively
> only checked for the default cache mode case, but not for an explicitly
> set cache.direct=off mode.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  blockdev.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 561cb81..c3422a1 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2283,8 +2283,10 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
>       *
>       * For now, simply forbidding the combination for all drivers will do. */
>      if (options->has_aio && options->aio == BLOCKDEV_AIO_OPTIONS_NATIVE) {
> -        bool direct = options->cache->has_direct && options->cache->direct;
> -        if (!options->has_cache && !direct) {
> +        bool direct = options->has_cache &&
> +                      options->cache->has_direct &&
> +                      options->cache->direct;
> +        if (!direct) {
>              error_setg(errp, "aio=native requires cache.direct=true");
>              goto fail;
>          }
> -- 
> 1.8.1.4
> 
> 
Reviewed-by: Benoit Canet <benoit@irqsave.net>