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_DIAGASSERT that RW_FLAGMASK bits are not set in a thread pointer.

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rwlock uses lower bits of a thread pointer for flags in the lock owner
field.  Assert that the pointer is properly aligned and those bits are
actually free to use.  This may not be the case when a program uses
its own allocator that can return less aligned pointers.
This commit is contained in:
uwe 2019-12-15 23:13:33 +00:00
parent 61243f61b7
commit 067b84db7c
1 changed files with 6 additions and 2 deletions
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8
lib/libpthread/pthread_rwlock.c
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@ -1,4 +1,4 @@
/* $NetBSD: pthread_rwlock.c,v 1.34 2016/07/03 14:24:58 christos Exp $ */
/* $NetBSD: pthread_rwlock.c,v 1.35 2019/12/15 23:13:33 uwe Exp $ */
/*-
* Copyright (c) 2002, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -30,11 +30,12 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_rwlock.c,v 1.34 2016/07/03 14:24:58 christos Exp $");
__RCSID("$NetBSD: pthread_rwlock.c,v 1.35 2019/12/15 23:13:33 uwe Exp $");
#include <sys/types.h>
#include <sys/lwpctl.h>
#include <assert.h>
#include <time.h>
#include <errno.h>
#include <stddef.h>
@ -275,6 +276,7 @@ pthread__rwlock_wrlock(pthread_rwlock_t *ptr, const struct timespec *ts)
int error;
self = pthread__self();
_DIAGASSERT(((uintptr_t)self & RW_FLAGMASK) == 0);
#ifdef ERRORCHECK
if (ptr->ptr_magic != _PT_RWLOCK_MAGIC)
@ -373,6 +375,7 @@ pthread_rwlock_trywrlock(pthread_rwlock_t *ptr)
#endif
self = pthread__self();
_DIAGASSERT(((uintptr_t)self & RW_FLAGMASK) == 0);
for (owner = (uintptr_t)ptr->ptr_owner;; owner = next) {
if (owner != 0)
@ -509,6 +512,7 @@ pthread_rwlock_unlock(pthread_rwlock_t *ptr)
*/
self = pthread__self();
if ((thread = PTQ_FIRST(&ptr->ptr_wblocked)) != NULL) {
_DIAGASSERT(((uintptr_t)thread & RW_FLAGMASK) == 0);
new = (uintptr_t)thread | RW_WRITE_LOCKED;
if (PTQ_NEXT(thread, pt_sleep) != NULL)