6209 libc mutexes break kernel writers hearts

Reviewed by: Jerry Jelinek <[email protected]> Reviewed by: Josef 'Jeff' Sipek <[email protected]> Reviewed by: Dan McDonald <[email protected]> Reviewed by: Garrett D'Amore <[email protected]> Approved by: Dan McDonald <[email protected]>
illumos · Sep 14, 2015 · 0d045c0 · 0d045c0
1 parent 7bbfa3e
commit 0d045c0
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Showing 7 changed files with 70 additions and 5 deletions.
diff --git a/usr/src/head/synch.h b/usr/src/head/synch.h
@@ -211,6 +211,12 @@ void smt_pause(void);
 
 #endif /* _ASM */
 
+/*
+ * Panicking versions of our favorite friends.
+ */
+void mutex_enter(mutex_t *);
+void mutex_exit(mutex_t *);
+
 #ifdef	__cplusplus
 }
 #endif

diff --git a/usr/src/lib/libc/inc/thr_uberdata.h b/usr/src/lib/libc/inc/thr_uberdata.h
@@ -23,7 +23,7 @@
  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 /*
- * Copyright (c) 2014, Joyent, Inc. All rights reserved.
+ * Copyright (c) 2015, Joyent, Inc.
  */
 
 #ifndef _THR_UBERDATA_H
@@ -1229,6 +1229,8 @@ extern	void	getgregs(ulwp_t *, gregset_t);
 extern	void	setgregs(ulwp_t *, gregset_t);
 extern	void	thr_panic(const char *);
 #pragma rarely_called(thr_panic)
+extern	void	mutex_panic(mutex_t *, const char *);
+#pragma rarely_called(mutex_panic)
 extern	ulwp_t	*find_lwp(thread_t);
 extern	void	finish_init(void);
 extern	void	update_sched(ulwp_t *);

diff --git a/usr/src/lib/libc/port/mapfile-vers b/usr/src/lib/libc/port/mapfile-vers
@@ -2915,6 +2915,8 @@ $endif
 	msgctl64;
 	__multi_innetgr;
 	_mutex_destroy		{ FLAGS = NODYNSORT };
+	mutex_enter;
+	mutex_exit;
 	mutex_held;
 	_mutex_init		{ FLAGS = NODYNSORT };
 	_mutex_unlock		{ FLAGS = NODYNSORT };

diff --git a/usr/src/lib/libc/port/threads/assfail.c b/usr/src/lib/libc/port/threads/assfail.c
@@ -25,6 +25,7 @@
  */
 /*
  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright 2015 Joyent, Inc.
  */
 
 #include "lint.h"
@@ -36,6 +37,8 @@ ulwp_t *panic_thread;
 static mutex_t assert_lock = DEFAULTMUTEX;
 static ulwp_t *assert_thread = NULL;
 
+mutex_t *panic_mutex = NULL;
+
 /*
  * Called from __assert() to set panicstr and panic_thread.
  */
@@ -129,6 +132,13 @@ aio_panic(const char *why)
 	common_panic("*** libc aio system failure: ", why);
 }
 
+void
+mutex_panic(mutex_t *mp, const char *why)
+{
+	panic_mutex = mp;
+	common_panic("*** libc mutex system failure: ", why);
+}
+
 /*
  * Utility function for converting a long integer to a string, avoiding stdio.
  * 'base' must be one of 10 or 16

diff --git a/usr/src/lib/libc/port/threads/synch.c b/usr/src/lib/libc/port/threads/synch.c
@@ -22,6 +22,7 @@
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright 2015, Joyent, Inc.
  */
 
 #include "lint.h"
@@ -2314,6 +2315,29 @@ mutex_lock(mutex_t *mp)
 	return (mutex_lock_impl(mp, NULL));
 }
 
+void
+mutex_enter(mutex_t *mp)
+{
+	int ret;
+	int attr = mp->mutex_type & ALL_ATTRIBUTES;
+
+	/*
+	 * Require LOCK_ERRORCHECK, accept LOCK_RECURSIVE.
+	 */
+	if (attr != LOCK_ERRORCHECK &&
+	    attr != (LOCK_ERRORCHECK | LOCK_RECURSIVE)) {
+		mutex_panic(mp, "mutex_enter: bad mutex type");
+	}
+	ret = mutex_lock(mp);
+	if (ret == EDEADLK) {
+		mutex_panic(mp, "recursive mutex_enter");
+	} else if (ret == EAGAIN) {
+		mutex_panic(mp, "excessive recursive mutex_enter");
+	} else if (ret != 0) {
+		mutex_panic(mp, "unknown mutex_enter failure");
+	}
+}
+
 int
 pthread_mutex_timedlock(pthread_mutex_t *_RESTRICT_KYWD mp,
 	const struct timespec *_RESTRICT_KYWD abstime)
@@ -2573,6 +2597,25 @@ mutex_unlock(mutex_t *mp)
 	return (mutex_unlock_internal(mp, 0));
 }
 
+void
+mutex_exit(mutex_t *mp)
+{
+	int ret;
+	int attr = mp->mutex_type & ALL_ATTRIBUTES;
+
+	if (attr != LOCK_ERRORCHECK &&
+	    attr != (LOCK_ERRORCHECK | LOCK_RECURSIVE)) {
+		mutex_panic(mp, "mutex_exit: bad mutex type");
+	}
+	ret = mutex_unlock(mp);
+	if (ret == EPERM) {
+		mutex_panic(mp, "mutex_exit: not owner");
+	} else if (ret != 0) {
+		mutex_panic(mp, "unknown mutex_exit failure");
+	}
+
+}
+
 /*
  * Internally to the library, almost all mutex lock/unlock actions
  * go through these lmutex_ functions, to protect critical regions.

diff --git a/usr/src/lib/libzpool/common/kernel.c b/usr/src/lib/libzpool/common/kernel.c
@@ -156,7 +156,7 @@ zmutex_destroy(kmutex_t *mp)
 }
 
 void
-mutex_enter(kmutex_t *mp)
+zmutex_enter(kmutex_t *mp)
 {
 	ASSERT(mp->initialized == B_TRUE);
 	ASSERT(mp->m_owner != (void *)-1UL);
@@ -181,7 +181,7 @@ mutex_tryenter(kmutex_t *mp)
 }
 
 void
-mutex_exit(kmutex_t *mp)
+zmutex_exit(kmutex_t *mp)
 {
 	ASSERT(mp->initialized == B_TRUE);
 	ASSERT(mutex_owner(mp) == curthread);

diff --git a/usr/src/lib/libzpool/common/sys/zfs_context.h b/usr/src/lib/libzpool/common/sys/zfs_context.h
@@ -225,11 +225,13 @@ extern int _mutex_destroy(mutex_t *mp);
 
 #define	mutex_init(mp, b, c, d)		zmutex_init((kmutex_t *)(mp))
 #define	mutex_destroy(mp)		zmutex_destroy((kmutex_t *)(mp))
+#define	mutex_enter(mp)			zmutex_enter(mp)
+#define	mutex_exit(mp)			zmutex_exit(mp)
 
 extern void zmutex_init(kmutex_t *mp);
 extern void zmutex_destroy(kmutex_t *mp);
-extern void mutex_enter(kmutex_t *mp);
-extern void mutex_exit(kmutex_t *mp);
+extern void zmutex_enter(kmutex_t *mp);
+extern void zmutex_exit(kmutex_t *mp);
 extern int mutex_tryenter(kmutex_t *mp);
 extern void *mutex_owner(kmutex_t *mp);