Prevent a xenagent timeout on S3/S4 transition.

Prevent a xenagent timeout (and live kernel dump) on S3/S4 transition by
changing CXenIfaceCreator::Log to use TryEnterCriticalSection.
Otherwise, a timeout occurs when the service control handler fails to
return due to attempting to enter a critical section object that the
main service thread already owns while responding to the
control/shutdown xenstore watch.

Signed-off-by: Troy Crosley <troycrosley@gmail.com>
[Re-ordered if statement]
Signed-off-by: Paul Durrant <paul@xen.org>

diff --git a/src/xenagent/service.cpp b/src/xenagent/service.cpp
index 26c63a2a52a0e76a16303a9b4b99656fadccfc36..e5c817d825b7e8ed32dc6ce205abc2cdc47a7021 100644 (file)
--- a/src/xenagent/service.cpp
+++ b/src/xenagent/service.cpp
@@ -107,9 +107,9 @@ void CXenIfaceCreator::OnPowerEvent(DWORD evt, LPVOID data)
 void CXenIfaceCreator::Log(const char* message)
 {
     // if possible, send to xeniface to forward to logs
-    CCritSec crit(&m_crit);
-    if (m_device) {
+    if (m_device && TryEnterCriticalSection(&m_crit)) {
         m_device->Log(message);
+        LeaveCriticalSection(&m_crit);
     }
 }