[lttng-dev] [PATCH lttng-tools] Fix: Dereference after NULL check in consumer

[Jérémie Galarneau]

Merged, thanks!

Jérémie

On Tue, May 17, 2016 at 11:46 AM, Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
> Dereference after NULL check in consumer discarded events/lost packets
> commands.
>
> Found by Coverity:
>
> CID 1040158 (#1 of 2): Dereference after null check (FORWARD_NULL)24.
> var_deref_op: Dereferencing null pointer channel.
>
> CID 1040158 (#2 of 2): Dereference after null check (FORWARD_NULL)24.
> var_deref_op: Dereferencing null pointer channel.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> ---
>  src/common/kernel-consumer/kernel-consumer.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
> index 9e35404..3216903 100644
> --- a/src/common/kernel-consumer/kernel-consumer.c
> +++ b/src/common/kernel-consumer/kernel-consumer.c
> @@ -969,18 +969,18 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
>                 uint64_t id = msg.u.discarded_events.session_id;
>                 uint64_t key = msg.u.discarded_events.channel_key;
>
> +               DBG("Kernel consumer discarded events command for session id %"
> +                               PRIu64 ", channel key %" PRIu64, id, key);
> +
>                 channel = consumer_find_channel(key);
>                 if (!channel) {
>                         ERR("Kernel consumer discarded events channel %"
>                                         PRIu64 " not found", key);
> -                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
> +                       ret = 0;
> +               } else {
> +                       ret = channel->discarded_events;
>                 }
>
> -               DBG("Kernel consumer discarded events command for session id %"
> -                               PRIu64 ", channel key %" PRIu64, id, key);
> -
> -               ret = channel->discarded_events;
> -
>                 health_code_update();
>
>                 /* Send back returned value to session daemon */
> @@ -999,18 +999,18 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
>                 uint64_t id = msg.u.lost_packets.session_id;
>                 uint64_t key = msg.u.lost_packets.channel_key;
>
> +               DBG("Kernel consumer lost packets command for session id %"
> +                               PRIu64 ", channel key %" PRIu64, id, key);
> +
>                 channel = consumer_find_channel(key);
>                 if (!channel) {
>                         ERR("Kernel consumer lost packets channel %"
>                                         PRIu64 " not found", key);
> -                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
> +                       ret = 0;
> +               } else {
> +                       ret = channel->lost_packets;
>                 }
>
> -               DBG("Kernel consumer lost packets command for session id %"
> -                               PRIu64 ", channel key %" PRIu64, id, key);
> -
> -               ret = channel->lost_packets;
> -
>                 health_code_update();
>
>                 /* Send back returned value to session daemon */
> --
> 2.1.4
>



-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com