From: Mukund Sivaraman <muks@isc.org>
Date: Sun, 21 Oct 2012 23:34:54 +0000 (+0530)
Subject: [2198] Check for EDEADLK too when using Mutex::tryLock()
X-Git-Tag: trac2402_base~10^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59d1e7799c13b01d24276dbd6377934d50ca0749;p=thirdparty%2Fkea.git

[2198] Check for EDEADLK too when using Mutex::tryLock()
---

diff --git a/src/lib/util/threads/sync.cc b/src/lib/util/threads/sync.cc
index bcb391a79e..f812556005 100644
--- a/src/lib/util/threads/sync.cc
+++ b/src/lib/util/threads/sync.cc
@@ -132,7 +132,13 @@ 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));