From a1eb8cb5dab06dd23c256d03d82ef6b0efc4b6c6 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 30 Mar 2011 10:32:45 -0400
Subject: [PATCH] avoid crash on stupid but allowable usage of
pthread_mutex_unlock
unlocking an unlocked mutex is not UB for robust or error-checking
mutexes, so we must avoid calling __pthread_self (which might crash
due to lack of thread-register initialization) until after checking
that the mutex is locked.
---
src/thread/pthread_mutex_unlock.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 5855db0b..6c4d7f22 100644
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -5,9 +5,11 @@ int pthread_mutex_unlock(pthread_mutex_t *m)
pthread_t self;
if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
+ if (!m->_m_lock)
+ return EPERM;
self = __pthread_self();
if ((m->_m_lock&0x1fffffff) != self->tid)
- return EPERM;
+ return EPERM;
if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
return 0;
if (m->_m_type >= 4) {
--
2.40.0