diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index 7517f1284ed..2e6c3aca0a7 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -312,6 +312,15 @@ func mallocinit() {
 		// When that gets used up, we'll start asking the kernel
 		// for any memory anywhere.
 
+		// We want to start the arena low, but if we're linked
+		// against C code, it's possible global constructors
+		// have called malloc and adjusted the process' brk.
+		// Query the brk so we can avoid trying to map the
+		// arena over it (which will cause the kernel to put
+		// the arena somewhere else, likely at a high
+		// address).
+		procBrk := sbrk0()
+
 		// If we fail to allocate, try again with a smaller arena.
 		// This is necessary on Android L where we share a process
 		// with ART, which reserves virtual memory aggressively.
@@ -336,6 +345,12 @@ func mallocinit() {
 			// to a MB boundary.
 			p = round(firstmoduledata.end+(1<<18), 1<<20)
 			pSize = bitmapSize + spansSize + arenaSize + _PageSize
+			if p <= procBrk && procBrk < p+pSize {
+				// Move the start above the brk,
+				// leaving some room for future brk
+				// expansion.
+				p = round(procBrk+(1<<20), 1<<20)
+			}
 			p = uintptr(sysReserve(unsafe.Pointer(p), pSize, &reserved))
 			if p != 0 {
 				break
diff --git a/src/runtime/stubs_linux.go b/src/runtime/stubs_linux.go
new file mode 100644
index 00000000000..d10f657197f
--- /dev/null
+++ b/src/runtime/stubs_linux.go
@@ -0,0 +1,9 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package runtime
+
+func sbrk0() uintptr
diff --git a/src/runtime/stubs_nonlinux.go b/src/runtime/stubs_nonlinux.go
new file mode 100644
index 00000000000..e1ea05cf0b1
--- /dev/null
+++ b/src/runtime/stubs_nonlinux.go
@@ -0,0 +1,12 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !linux
+
+package runtime
+
+// sbrk0 returns the current process brk, or 0 if not implemented.
+func sbrk0() uintptr {
+	return 0
+}
diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
index a369792d78d..2eb4b1e6651 100644
--- a/src/runtime/sys_linux_386.s
+++ b/src/runtime/sys_linux_386.s
@@ -596,3 +596,12 @@ TEXT runtime·socket(SB),NOSPLIT,$0-16
 	INVOKE_SYSCALL
 	MOVL	AX, ret+12(FP)
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-4
+	// Implemented as brk(NULL).
+	MOVL	$45, AX  // syscall - brk
+	MOVL	$0, BX  // NULL
+	INVOKE_SYSCALL
+	MOVL	AX, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index be6f396cfa4..c2b1376fa9c 100644
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -598,3 +598,12 @@ TEXT runtime·socket(SB),NOSPLIT,$0-20
 	SYSCALL
 	MOVL	AX, ret+16(FP)
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-8
+	// Implemented as brk(NULL).
+	MOVQ	$0, DI
+	MOVL	$12, AX  // syscall entry
+	SYSCALL
+	MOVQ	AX, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 8afc71f059c..0244613e676 100644
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -48,6 +48,7 @@
 #define SYS_access (SYS_BASE + 33)
 #define SYS_connect (SYS_BASE + 283)
 #define SYS_socket (SYS_BASE + 281)
+#define SYS_brk (SYS_BASE + 45)
 
 #define ARM_BASE (SYS_BASE + 0x0f0000)
 
@@ -504,3 +505,12 @@ TEXT runtime·socket(SB),NOSPLIT,$0
 	SWI	$0
 	MOVW	R0, ret+12(FP)
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-4
+	// Implemented as brk(NULL).
+	MOVW	$0, R0
+	MOVW	$SYS_brk, R7
+	SWI	$0
+	MOVW	R0, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
index 204aee7c511..e921f9906cf 100644
--- a/src/runtime/sys_linux_arm64.s
+++ b/src/runtime/sys_linux_arm64.s
@@ -46,6 +46,7 @@
 #define SYS_faccessat		48
 #define SYS_socket		198
 #define SYS_connect		203
+#define SYS_brk			214
 
 TEXT runtime·exit(SB),NOSPLIT,$-8-4
 	MOVW	code+0(FP), R0
@@ -483,3 +484,12 @@ TEXT runtime·socket(SB),NOSPLIT,$0-20
 	SVC
 	MOVW	R0, ret+16(FP)
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-8
+	// Implemented as brk(NULL).
+	MOVD	$0, R0
+	MOVD	$SYS_brk, R8
+	SVC
+	MOVD	R0, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_mips64x.s b/src/runtime/sys_linux_mips64x.s
index a4bcc72dd8c..27de7b0901c 100644
--- a/src/runtime/sys_linux_mips64x.s
+++ b/src/runtime/sys_linux_mips64x.s
@@ -45,6 +45,7 @@
 #define SYS_epoll_wait		5209
 #define SYS_clock_gettime	5222
 #define SYS_epoll_create1	5285
+#define SYS_brk			5012
 
 TEXT runtime·exit(SB),NOSPLIT,$-8-4
 	MOVW	code+0(FP), R4
@@ -426,3 +427,12 @@ TEXT runtime·closeonexec(SB),NOSPLIT,$-8
 	MOVV	$SYS_fcntl, R2
 	SYSCALL
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$-8-8
+	// Implemented as brk(NULL).
+	MOVV	$0, R4
+	MOVV	$SYS_brk, R2
+	SYSCALL
+	MOVV	R2, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
index a9c556dd784..39bd731a4dd 100644
--- a/src/runtime/sys_linux_mipsx.s
+++ b/src/runtime/sys_linux_mipsx.s
@@ -45,6 +45,7 @@
 #define SYS_epoll_wait		    4250
 #define SYS_clock_gettime	    4263
 #define SYS_epoll_create1	    4326
+#define SYS_brk			    4045
 
 TEXT runtime·exit(SB),NOSPLIT,$0-4
 	MOVW	code+0(FP), R4
@@ -465,3 +466,12 @@ TEXT runtime·closeonexec(SB),NOSPLIT,$0-4
 	MOVW	$SYS_fcntl, R2
 	SYSCALL
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-4
+	// Implemented as brk(NULL).
+	MOVW	$0, R4
+	MOVW	$SYS_brk, R2
+	SYSCALL
+	MOVW	R2, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index ef7dab21b75..2b2aa61d068 100644
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -21,6 +21,7 @@
 #define SYS_close		  6
 #define SYS_getpid		 20
 #define SYS_kill		 37
+#define SYS_brk			 45
 #define SYS_fcntl		 55
 #define SYS_gettimeofday	 78
 #define SYS_select		 82	// always return -ENOSYS
@@ -422,3 +423,11 @@ TEXT runtime·closeonexec(SB),NOSPLIT|NOFRAME,$0
 	MOVD    $1, R5  // FD_CLOEXEC
 	SYSCALL	$SYS_fcntl
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT|NOFRAME,$0
+	// Implemented as brk(NULL).
+	MOVD	$0, R3
+	SYSCALL	$SYS_brk
+	MOVD	R3, ret+0(FP)
+	RET
diff --git a/src/runtime/sys_linux_s390x.s b/src/runtime/sys_linux_s390x.s
index 2291718074f..b8099e25538 100644
--- a/src/runtime/sys_linux_s390x.s
+++ b/src/runtime/sys_linux_s390x.s
@@ -16,6 +16,7 @@
 #define SYS_close                 6
 #define SYS_getpid               20
 #define SYS_kill                 37
+#define SYS_brk			 45
 #define SYS_fcntl                55
 #define SYS_gettimeofday         78
 #define SYS_mmap                 90
@@ -434,3 +435,12 @@ TEXT runtime·closeonexec(SB),NOSPLIT|NOFRAME,$0
 	MOVW	$SYS_fcntl, R1
 	SYSCALL
 	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT|NOFRAME,$0-8
+	// Implemented as brk(NULL).
+	MOVD	$0, R2
+	MOVW	$SYS_brk, R1
+	SYSCALL
+	MOVD	R2, ret+0(FP)
+	RET