Re: [dpdk-stable] [PATCH v2 2/3] vhost: fix fd leak in dirty logging setup

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 11/9/20 1:07 PM, Xia, Chenbo wrote:
> Hi Maxime,
> 
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Monday, November 9, 2020 7:26 PM
>> To: dev@dpdk.org; Ding, Xuan <xuan.ding@intel.com>;
>> stephen@networkplumber.org; thomas@monjalon.net; stable@dpdk.org; Xia,
>> Chenbo <chenbo.xia@intel.com>
>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Subject: [PATCH v2 2/3] vhost: fix fd leak in dirty logging setup
>>
>> This patch fixes a file descriptor leak which happens
>> in the error path of vhost_user_set_log_base().
>>
>> Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application")
>> Cc: stable@dpdk.org
>>
>> Reported-by: Xuan Ding <xuan.ding@intel.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>  lib/librte_vhost/vhost_user.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index 473fd778ca..e4ad5f6baf 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -2076,7 +2076,7 @@ vhost_user_set_log_base(struct virtio_net **pdev,
>> struct VhostUserMsg *msg,
>>
>>  	if (fd < 0) {
>>  		VHOST_LOG_CONFIG(ERR, "invalid log fd: %d\n", fd);
>> -		return RTE_VHOST_MSG_RESULT_ERR;
>> +		goto close_msg_fds;
> 
> I remember we have agreed on simply return here? As I look back to v1, I think
> you may modify the wrong place. Because I see another 'goto close_msg_fds' is
> deleted compared with v1 😊.
> 
>  	if (msg->size != sizeof(VhostUserLog)) {
>  		VHOST_LOG_CONFIG(ERR,
>  			"invalid log base msg size: %"PRId32" != %d\n",
>  			msg->size, (int)sizeof(VhostUserLog));
> -		return RTE_VHOST_MSG_RESULT_ERR;
> +		goto close_msg_fds;


... I need more coffee it seems! Of course you are right, I reverted the
wrong line. Thanks for catching it.

v3 on its way.

Thanks,
Maxime

> Thanks!
> Chenbo
> 
>>  	}
>>
>>  	if (msg->size != sizeof(VhostUserLog)) {
>> @@ -2094,7 +2094,7 @@ vhost_user_set_log_base(struct virtio_net **pdev,
>> struct VhostUserMsg *msg,
>>  		VHOST_LOG_CONFIG(ERR,
>>  			"log offset %#"PRIx64" and log size %#"PRIx64"
>> overflow\n",
>>  			off, size);
>> -		return RTE_VHOST_MSG_RESULT_ERR;
>> +		goto close_msg_fds;
>>  	}
>>
>>  	VHOST_LOG_CONFIG(INFO,
>> @@ -2131,6 +2131,10 @@ vhost_user_set_log_base(struct virtio_net **pdev,
>> struct VhostUserMsg *msg,
>>  	msg->fd_num = 0;
>>
>>  	return RTE_VHOST_MSG_RESULT_REPLY;
>> +
>> +close_msg_fds:
>> +	close_msg_fds(msg);
>> +	return RTE_VHOST_MSG_RESULT_ERR;
>>  }
>>
>>  static int vhost_user_set_log_fd(struct virtio_net **pdev __rte_unused,
>> --
>> 2.26.2
>