BIND 10 master, updated. 42c638e07a45b69d902a51b35838ae21ac19d116 [master] Check for EDEADLK too when using Mutex::tryLock()

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- Log -----------------------------------------------------------------
commit 42c638e07a45b69d902a51b35838ae21ac19d116
Author: Mukund Sivaraman <muks at isc.org>
Date:   Tue Oct 16 11:54:19 2012 +0530

    [master] Check for EDEADLK too when using Mutex::tryLock()

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Summary of changes:
 src/lib/util/threads/lock.cc |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

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diff --git a/src/lib/util/threads/lock.cc b/src/lib/util/threads/lock.cc
index acc73d6..c3c818e 100644
--- a/src/lib/util/threads/lock.cc
+++ b/src/lib/util/threads/lock.cc
@@ -123,7 +123,13 @@ bool
 Mutex::tryLock() {
     assert(impl_ != NULL);
     const int result = pthread_mutex_trylock(&impl_->mutex);
-    if (result == EBUSY) {
+
+    // In the case of pthread_mutex_trylock(), if it is called on a
+    // locked mutex from the same thread, some platforms (such as fedora
+    // and debian) return EBUSY whereas others (such as centos 5) return
+    // EDEADLK. We return false and don't pass the lock attempt in both
+    // cases.
+    if (result == EBUSY || result == EDEADLK) {
         return (false);
     } else if (result != 0) {
         isc_throw(isc::InvalidOperation, std::strerror(result));