diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
index a800ea17..165ad700 100644
--- a/src/lib/libc/stdlib/malloc.c
+++ b/src/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.c,v 1.170 2014/07/09 19:11:00 tedu Exp $	*/
+/*	$OpenBSD: malloc.c,v 1.171 2014/08/18 14:34:58 tedu Exp $	*/
 /*
  * Copyright (c) 2008, 2010, 2011 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -93,6 +93,15 @@
 #define MQUERY(a, sz)	mquery((a), (size_t)(sz), PROT_READ | PROT_WRITE, \
     MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, (off_t)0)
 
+#define KERNENTER() if (__isthreaded) do { \
+	malloc_active--; \
+	_MALLOC_UNLOCK(); \
+} while (0)
+#define KERNEXIT() if (__isthreaded) do { \
+	_MALLOC_LOCK(); \
+	malloc_active++; \
+} while (0)
+
 struct region_info {
 	void *p;		/* page; low bits used to mark chunks */
 	uintptr_t size;		/* size for pages, or chunk_info pointer */
@@ -312,7 +321,8 @@ unmap(struct dir_info *d, void *p, size_t sz)
 	}
 
 	if (psz > mopts.malloc_cache) {
-		if (munmap(p, sz))
+		i = munmap(p, sz);
+		if (i)
 			wrterror("munmap", p);
 		STATS_SUB(d->malloc_used, sz);
 		return;
@@ -396,7 +406,9 @@ map(struct dir_info *d, size_t sz, int zero_fill)
 		return MAP_FAILED;
 	}
 	if (psz > d->free_regions_size) {
+		KERNENTER();
 		p = MMAP(sz);
+		KERNEXIT();
 		if (p != MAP_FAILED)
 			STATS_ADD(d->malloc_used, sz);
 		/* zero fill not needed */
@@ -408,13 +420,13 @@ map(struct dir_info *d, size_t sz, int zero_fill)
 		if (r->p != NULL) {
 			if (r->size == psz) {
 				p = r->p;
+				r->p = NULL;
+				r->size = 0;
+				d->free_regions_size -= psz;
 				if (mopts.malloc_freeunmap)
 					mprotect(p, sz, PROT_READ | PROT_WRITE);
 				if (mopts.malloc_hint)
 					madvise(p, sz, MADV_NORMAL);
-				r->p = NULL;
-				r->size = 0;
-				d->free_regions_size -= psz;
 				if (zero_fill)
 					memset(p, 0, sz);
 				else if (mopts.malloc_junk == 2 &&
@@ -440,11 +452,13 @@ map(struct dir_info *d, size_t sz, int zero_fill)
 			memset(p, SOME_FREEJUNK, sz);
 		return p;
 	}
+	if (d->free_regions_size > mopts.malloc_cache)
+		wrterror("malloc cache", NULL);
+	KERNENTER();
 	p = MMAP(sz);
+	KERNEXIT();
 	if (p != MAP_FAILED)
 		STATS_ADD(d->malloc_used, sz);
-	if (d->free_regions_size > mopts.malloc_cache)
-		wrterror("malloc cache", NULL);
 	/* zero fill not needed */
 	return p;
 }