Re: [dpdk-dev] [PATCH 1/2] graph: fix memory leak

["Min Hu (Connor)" <humin29@huawei.com>]

在 2021/5/4 22:15, David Marchand 写道:
> On Thu, Apr 22, 2021 at 1:52 PM Min Hu (Connor) <humin29@huawei.com> wrote:
>>
>> From: HongBo Zheng <zhenghongbo3@huawei.com>
>>
>> Fix function 'stats_mem_populate' return without
>> free dynamic memory referenced by 'stats'.
>>
>> Fixes: af1ae8b6a32c ("graph: implement stats")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: HongBo Zheng <zhenghongbo3@huawei.com>
>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>> ---
>>   lib/librte_graph/graph_stats.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_graph/graph_stats.c b/lib/librte_graph/graph_stats.c
>> index 125e08d..f698bb3 100644
>> --- a/lib/librte_graph/graph_stats.c
>> +++ b/lib/librte_graph/graph_stats.c
>> @@ -174,7 +174,7 @@ stats_mem_populate(struct rte_graph_cluster_stats **stats_in,
>>          cluster->stat.hz = rte_get_timer_hz();
>>          node = graph_node_id_to_ptr(graph, id);
>>          if (node == NULL)
>> -               SET_ERR_JMP(ENOENT, err, "Failed to find node %s in graph %s",
>> +               SET_ERR_JMP(ENOENT, free, "Failed to find node %s in graph %s",
>>                              graph_node->node->name, graph->name);
>>          cluster->nodes[cluster->nb_nodes++] = node;
>>
>> @@ -183,6 +183,8 @@ stats_mem_populate(struct rte_graph_cluster_stats **stats_in,
>>          *stats_in = stats;
>>
>>          return 0;
>> +free:
>> +       free(stats);
>>   err:
>>          return -rte_errno;
>>   }
> 
> We have a double free with this change.
> 
Hi, David, I will set "*stats_in " to NULL.
As free(NULL) will just return and will not
result bugs.
> If realloc on stats returns the same location, but node lookup fails,
> stats_in is left untouched and still points at the original stats
> location.
> This location is then freed in the free: label, and later is freed in
> stats_mem_fini() from caller.
> 
>