[lttng-dev] [PATCH lttng-tools] Fix: Missing read locks on access to consumerd's channel hash table

[Mathieu Desnoyers]

* Jérémie Galarneau (jeremie.galarneau at efficios.com) wrote:
> Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>

this had been merged into lttng-tools as:

commit c7260a81b6c99282da7c59b6124381f92c637658
Author: Jérémie Galarneau <jeremie.galarneau at efficios.com>
Date:   Mon Jun 3 23:19:59 2013 -0400

    Fix: Missing RCU locks on access to consumerd's channel ht
    
    Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>
    Signed-off-by: David Goulet <dgoulet at efficios.com>

For both stable-2.2 and master.


> ---
>  src/common/consumer.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/src/common/consumer.c b/src/common/consumer.c
> index 3709092..5f38375 100644
> --- a/src/common/consumer.c
> +++ b/src/common/consumer.c
> @@ -2716,16 +2716,21 @@ restart:
>  
>  						lttng_ht_node_init_u64(&chan->wait_fd_node,
>  							chan->wait_fd);
> +						rcu_read_lock();
>  						lttng_ht_add_unique_u64(channel_ht,
>  								&chan->wait_fd_node);
> +						rcu_read_unlock();
>  						/* Add channel to the global poll events list */
>  						lttng_poll_add(&events, chan->wait_fd,
>  								LPOLLIN | LPOLLPRI);
>  						break;
>  					case CONSUMER_CHANNEL_DEL:
>  					{
> +						rcu_read_lock();
>  						chan = consumer_find_channel(key);
> +
>  						if (!chan) {
> +							rcu_read_unlock();
>  							ERR("UST consumer get channel key %" PRIu64 " not found for del channel", key);
>  							break;
>  						}
> @@ -2741,6 +2746,7 @@ restart:
>  						if (!uatomic_sub_return(&chan->refcount, 1)) {
>  							consumer_del_channel(chan);
>  						}
> +						rcu_read_unlock();
>  						goto restart;
>  					}
>  					case CONSUMER_CHANNEL_QUIT:
> -- 
> 1.8.2.3
> 
> 
> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com