From 3d8905f85945d899192b113ae495e99894687c4f Mon Sep 17 00:00:00 2001
From: Rich Salz <rsalz@akamai.com>
Date: Thu, 18 Feb 2021 16:27:08 -0500
Subject: [PATCH] Fix error-checking compiles for mutex
Fixes: #14229
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14264)
---
INSTALL.md | 7 +++++++
crypto/threads_pthread.c | 2 +-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/INSTALL.md b/INSTALL.md
index 01c360e8d4..d6ef21d20e 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -1666,6 +1666,13 @@ most UNIX/Linux systems), and Windows threads. No other threading models are
supported. If your platform does not provide pthreads or Windows threads then
you should use `Configure` with the `no-threads` option.
+For pthreads, all locks are non-recursive. In addition, in a debug build,
+the mutex attribute `PTHREAD_MUTEX_ERRORCHECK` is used. If this is not
+available on your platform, you might have to add
+`-DOPENSSL_NO_MUTEX_ERRORCHECK` to your `Configure` invocation.
+(On Linux `PTHREAD_MUTEX_ERRORCHECK` is an enum value, so a built-in
+ifdef test cannot be used.)
+
Notes on shared libraries
-------------------------
diff --git a/crypto/threads_pthread.c b/crypto/threads_pthread.c
index 3004e1bd2f..e81f3cf1ef 100644
--- a/crypto/threads_pthread.c
+++ b/crypto/threads_pthread.c
@@ -55,7 +55,7 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
* We don't use recursive mutexes, but try to catch errors if we do.
*/
pthread_mutexattr_init(&attr);
-# if defined(NDEBUG) && defined(PTHREAD_MUTEX_ERRORCHECK)
+# if !defined(NDEBUG) && !defined(OPENSSL_NO_MUTEX_ERRORCHECK)
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
# else
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);