[PATCH 2/5] Watch BACKEND/state key for eject status

["Tu Dinh" <ngoc-tu.dinh@xxxxxxxxxx>]

The frontend eject thread watches for writes to BACKEND/online to detect
an orderly device eject. However, BACKEND/online is also written during
a forced removal of the VIF, where the entire backend key is removed
shortly after. This in turn causes NDIS to hang waiting for packets to
be returned, in the absence of hang detection.

Move the eject thread's watch onto BACKEND/state instead. This delays
the FrontendEject watch just enough that it fires after FdoScan, and so
leaves an opportunity for FdoScan to trigger a surprise removal.

Suggested-by: Paul Durrant <xadimgnik@xxxxxxxxx>
Signed-off-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
---
 src/xenvif/frontend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/xenvif/frontend.c b/src/xenvif/frontend.c
index 5311dea..5cdb9a1 100644
--- a/src/xenvif/frontend.c
+++ b/src/xenvif/frontend.c
@@ -1603,7 +1603,7 @@ FrontendPrepare(
     status = XENBUS_STORE(WatchAdd,
                           &Frontend->StoreInterface,
                           __FrontendGetBackendPath(Frontend),
-                          "online",
+                          "state",
                           ThreadGetEvent(Frontend->EjectThread),
                           &Frontend->Watch);
     if (!NT_SUCCESS(status))
-- 
2.53.0.windows.2



--
Ngoc Tu Dinh | Vates XCP-ng Developer

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