[libvirt] [PATCH 3/6] rpc: Plug memory leak on virNetClientSendInternal() error path

[Alex Jia]

On 12/01/2011 07:11 AM, Eric Blake wrote:
> On 11/29/2011 11:40 PM, Alex Jia wrote:
>> On 11/30/2011 02:26 PM, Wen Congyang wrote:
>>> At 11/30/2011 01:57 PM, ajia at redhat.com Write:
>>>> From: Alex Jia<ajia at redhat.com>
>>>>
>>>> Detected by Coverity. Leak introduced in commit 673adba.
>>>>
>>> So I think we should not free call if it is still on the queue.
>> Yeah, it's a inappropriate place, in addition, in 'cleanup' label, if
>> ret !=1, also will free 'all', then 'unlock' label still do this, the
>> following should be a right place:
>>
>> 1708     if (!client->sock || client->wantClose) {
>> 1709         virNetError(VIR_ERR_INTERNAL_ERROR, "%s",
>> 1710                     _("client socket is closed"));
>> *1711       VIR_FREE(call);*
>> 1712         goto unlock;
>> 1713     }
> Closer, but still not quite right either.  You solved the failure if
> !client->sock, but still left in the bug that a failed virCondInit did
> goto cleanup, which then did a call to virCondDestroy on uninitialized
> data, which is undefined by POSIX.
>
> Rearranging some code and consolidating to one label will solve both
> bugs (the leak if !client->sock, and the incorrect virCondDestroy call
> on virCondInit failure), while still avoiding to free call on a partial
> send.  Here's what I'm pushing under your name.
Yeah, I just saw codes again. Eric, thanks.
> diff --git c/src/rpc/virnetclient.c w/src/rpc/virnetclient.c
> index a738129..5165c8d 100644
> --- c/src/rpc/virnetclient.c
> +++ w/src/rpc/virnetclient.c
> @@ -1705,13 +1705,13 @@ static int
> virNetClientSendInternal(virNetClientPtr client,
>
>       virNetClientLock(client);
>
>       if (!client->sock || client->wantClose) {
>           virNetError(VIR_ERR_INTERNAL_ERROR, "%s",
>                       _("client socket is closed"));
> -        goto unlock;
> +        goto cleanup;
>       }
>
>       if (virCondInit(&call->cond)<  0) {
>           virNetError(VIR_ERR_INTERNAL_ERROR, "%s",
>                       _("cannot initialize condition variable"));
>           goto cleanup;
> @@ -1726,22 +1726,22 @@ static int
> virNetClientSendInternal(virNetClientPtr client,
>       call->expectReply = expectReply;
>       call->nonBlock = nonBlock;
>       call->haveThread = true;
>
>       ret = virNetClientIO(client, call);
>
> -cleanup:
>       /* If partially sent, then the call is still on the dispatch queue */
>       if (ret == 1) {
>           call->haveThread = false;
>       } else {
>           ignore_value(virCondDestroy(&call->cond));
> -        VIR_FREE(call);
>       }
>
> -unlock:
> +cleanup:
> +    if (ret != 1)
> +        VIR_FREE(call);
>       virNetClientUnlock(client);
>       return ret;
>   }
>
>
>   /*
>