Rémi Bernon : plugplay: Broadcast WM_DEVICECHANGE message asynchronously.

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: 196f033dec5bb9cf09d9e42ee54e8dc62b27b329
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=196f033dec5bb9cf09d9e42ee54e8dc62b27b329

Author: Rémi Bernon <rbernon at codeweavers.com>
Date:   Mon Feb 15 20:42:00 2021 +0100

plugplay: Broadcast WM_DEVICECHANGE message asynchronously.

It may otherwise trigger a nasty race condition, where:

1) For explorer.exe to register the CLSID_ShellWindows classes, it
   needs RpcSS service to be started,

2) services.exe may start WinePlugPlay service group first, waiting for
   its startup to complete,

3) during startup and early device enumeration, hidclass.sys may call
   IoSetDeviceInterfaceState, which calls plugplay_send_event [1],

4) plugplay_send_event tries to broadcast a WM_DEVICECHANGE message with
   BSF_QUERY, waiting for the individual threads to reply,

5) which times-out because window threads are waiting on explorer.exe
   to create its desktop window and reply to the WM_NULL SendMessage.

This happens more likely as there is threads with message queues
being started, each waiting on the desktop window to reply. Usually
explorer.exe is able to reply to some messages with the implicit
message processing while creating its window, but not all of them.

[1] Not completely sure how, it looks like some RPC too, but before
    RpcSs is started?

Signed-off-by: Rémi Bernon <rbernon at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>
(cherry picked from commit f5ca06016dbf41ea21752f34a16d9202bb7aaa02)
Signed-off-by: Michael Stefaniuc <mstefani at winehq.org>

---

 programs/plugplay/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/programs/plugplay/main.c b/programs/plugplay/main.c
index 19e02286312..1156cb9f036 100644
--- a/programs/plugplay/main.c
+++ b/programs/plugplay/main.c
@@ -142,8 +142,8 @@ void __cdecl plugplay_send_event( DWORD code, const BYTE *data, unsigned int siz
     struct listener *listener;
     struct event *event;
 
-    BroadcastSystemMessageW( BSF_FORCEIFHUNG | BSF_QUERY, NULL, WM_DEVICECHANGE, code, (LPARAM)data );
-    BroadcastSystemMessageW( BSF_FORCEIFHUNG | BSF_QUERY, NULL, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, 0 );
+    BroadcastSystemMessageW( 0, NULL, WM_DEVICECHANGE, code, (LPARAM)data );
+    BroadcastSystemMessageW( 0, NULL, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, 0 );
 
     EnterCriticalSection( &plugplay_cs );