[PATCH 1/2] winealsa: Don't acquire the sessions lock after the client lock.

[Andrew Eikum]

Signed-off-by: Andrew Eikum <aeikum at codeweavers.com>

On Thu, Dec 02, 2021 at 12:02:38PM +0000, Huw Davies wrote:
> This could lead to a deadlock with AudioSessionControl_GetState()
> which acquires the locks in the other order.
> 
> Signed-off-by: Huw Davies <huw at codeweavers.com>
> ---
>  dlls/winealsa.drv/mmdevdrv.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/dlls/winealsa.drv/mmdevdrv.c b/dlls/winealsa.drv/mmdevdrv.c
> index 7f25cdcce1b..5aa1b4aab63 100644
> --- a/dlls/winealsa.drv/mmdevdrv.c
> +++ b/dlls/winealsa.drv/mmdevdrv.c
> @@ -1344,10 +1344,12 @@ static HRESULT WINAPI AudioClient_Initialize(IAudioClient3 *iface,
>          }
>      }
>  
> +    EnterCriticalSection(&g_sessions_lock);
>      EnterCriticalSection(&This->lock);
>  
>      if(This->initted){
>          LeaveCriticalSection(&This->lock);
> +        LeaveCriticalSection(&g_sessions_lock);
>          return AUDCLNT_E_ALREADY_INITIALIZED;
>      }
>  
> @@ -1537,19 +1539,13 @@ static HRESULT WINAPI AudioClient_Initialize(IAudioClient3 *iface,
>      This->share = mode;
>      This->flags = flags;
>  
> -    EnterCriticalSection(&g_sessions_lock);
> -
>      hr = get_audio_session(sessionguid, This->parent, fmt->nChannels,
>              &This->session);
> -    if(FAILED(hr)){
> -        LeaveCriticalSection(&g_sessions_lock);
> +    if(FAILED(hr))
>          goto exit;
> -    }
>  
>      list_add_tail(&This->session->clients, &This->entry);
>  
> -    LeaveCriticalSection(&g_sessions_lock);
> -
>      This->initted = TRUE;
>  
>      TRACE("ALSA period: %lu frames\n", This->alsa_period_frames);
> @@ -1569,6 +1565,7 @@ exit:
>      }
>  
>      LeaveCriticalSection(&This->lock);
> +    LeaveCriticalSection(&g_sessions_lock);
>  
>      return hr;
>  }
> -- 
> 2.23.0
> 
>