Add PTHREAD_PRIO_INHERIT to POSIX Locks

base/synchronization/lock_impl_posix.cc

Index: base/synchronization/lock_impl_posix.cc
diff --git a/base/synchronization/lock_impl_posix.cc b/base/synchronization/lock_impl_posix.cc
index 5619adaf5d829df72f93fd57b0687d551fb9390d..90c3fa8cc3cfea55386f4698f2d9ac768a61d7da 100644
--- a/base/synchronization/lock_impl_posix.cc
+++ b/base/synchronization/lock_impl_posix.cc
@@ -8,26 +8,35 @@
 #include <string.h>
 
 #include "base/logging.h"
+#include "base/synchronization/lock.h"
+#include "base/version.h"
+
+#if defined(OS_LINUX)
+#include <gnu/libc-version.h>
+#endif
 
 namespace base {
 namespace internal {
 
 LockImpl::LockImpl() {
-#ifndef NDEBUG
-  // In debug, setup attributes for lock error checking.
   pthread_mutexattr_t mta;
   int rv = pthread_mutexattr_init(&mta);
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+#if PRIORITY_INHERITANCE_LOCKS_POSSIBLE()
+  if (PriorityInheritanceAvailable()) {
+    rv = pthread_mutexattr_setprotocol(&mta, PTHREAD_PRIO_INHERIT);
+  }
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+#endif
+#ifndef NDEBUG
+  // In debug, setup attributes for lock error checking.
   rv = pthread_mutexattr_settype(&mta, PTHREAD_MUTEX_ERRORCHECK);
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+#endif
   rv = pthread_mutex_init(&native_handle_, &mta);
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
   rv = pthread_mutexattr_destroy(&mta);
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
-#else
-  // In release, go with the default lock attributes.
-  pthread_mutex_init(&native_handle_, NULL);
-#endif
 }
 
 LockImpl::~LockImpl() {
@@ -51,5 +60,27 @@ void LockImpl::Unlock() {
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
 }
 
+// static
+bool LockImpl::PriorityInheritanceAvailable() {
+#if defined(OS_LINUX)
+  // Due to glibc Bug 14652, priority inheritance mutexes may deadlock with
+  // condition variables during recacquisition of the mutex after the condition
+  // variable is signalled. This bug was fixed in glibc 2.17.
+  Version version(gnu_get_libc_version());
+  if (!version.IsValid() || version.components().size() != 2)
+    return false;
+
+  uint32_t glibc_major_version = version.components()[0];
+  uint32_t glibc_minor_version = version.components()[1];
+
+  if (glibc_major_version < 2)
+    return false;
+
+  return glibc_major_version != 2 || glibc_minor_version >= 17;

[danakj, 2016/06/02 21:59:21]

You can use std::tie to combine these into one a < b check.

[robliao, 2016/06/02 22:17:48]

Neat! Done.

+#else
+  return true;
+#endif
+}
+
 }  // namespace internal
 }  // namespace base