runtime/cgo: use frame address to set g0 stack bound

This extends CL 419434 to all Unix targets. Rather than repeating
the code, pull all the similar code into a single function.

CL 419434 description:

For a cgo binary, at startup we set g0's stack bounds using the
address of a local variable (&size) in a C function x_cgo_init and
the stack size from pthread_attr_getstacksize. Normally, &size is
an address within the current stack frame. However, when  it is
compiled with ASAN, it may be instrumented to __asan_stack_malloc_0
and the address may not live in the current stack frame, causing
the stack bound to be set incorrectly, e.g. lo > hi.

Using __builtin_frame_address(0) to get the stack address instead.

Change-Id: I914a09d32c66a79515b6f700be18c690f3c0c77b
Reviewed-on: https://go-review.googlesource.com/c/go/+/517335
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>

src/runtime/cgo/gcc_darwin_amd64.c

@@ -14,12 +14,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	size_t size;
-
 	setg_gcc = setg;
-
-	size = pthread_get_stacksize_np(pthread_self());
-	g->stacklo = (uintptr)&size - size + 4096;
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_darwin_arm64.c

@@ -127,12 +127,9 @@ init_working_dir()
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	size_t size;
-
 	//fprintf(stderr, "x_cgo_init = %p\n", &x_cgo_init); // aid debugging in presence of ASLR
 	setg_gcc = setg;
-	size = pthread_get_stacksize_np(pthread_self());
-	g->stacklo = (uintptr)&size - size + 4096;
+	_cgo_set_stacklo(g, NULL);
 
 #if TARGET_OS_IPHONE
 	darwin_arm_init_mach_exception_handler();

src/runtime/cgo/gcc_dragonfly_amd64.c

@@ -16,14 +16,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_freebsd_386.c

@@ -16,14 +16,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_freebsd_amd64.c

@@ -18,7 +18,6 @@ void
 x_cgo_init(G *g, void (*setg)(void*))
 {
 	pthread_attr_t *attr;
-	size_t size;
 
 	// Deal with memory sanitizer/clang interaction.
 	// See gcc_linux_amd64.c for details.
@@ -27,10 +26,7 @@ x_cgo_init(G *g, void (*setg)(void*))
 	if (attr == NULL) {
 		fatalf("malloc failed: %s", strerror(errno));
 	}
-	pthread_attr_init(attr);
-	pthread_attr_getstacksize(attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(attr);
+	_cgo_set_stacklo(g, attr);
 	free(attr);
 }
 

src/runtime/cgo/gcc_freebsd_arm.c

@@ -27,14 +27,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_freebsd_arm64.c

@@ -17,14 +17,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_freebsd_riscv64.c

@@ -17,14 +17,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_libinit.c

@@ -82,6 +82,34 @@ _cgo_wait_runtime_init_done(void) {
 	return 0;
 }
 
+// _cgo_set_stacklo sets g->stacklo based on the stack size.
+// This is common code called from x_cgo_init, which is itself
+// called by rt0_go in the runtime package.
+void _cgo_set_stacklo(G *g, pthread_attr_t *pattr)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	// pattr can be passed in by the caller; see gcc_linux_amd64.c.
+	if (pattr == NULL) {
+		pattr = &attr;
+	}
+
+	pthread_attr_init(pattr);
+	pthread_attr_getstacksize(pattr, &size);
+
+	g->stacklo = (uintptr)(__builtin_frame_address(0)) - size + 4096;
+
+	// Sanity check the results now, rather than getting a
+	// morestack on g0 crash.
+	if (g->stacklo >= g->stackhi) {
+		fprintf(stderr, "runtime/cgo: bad stack bounds: lo=%p hi=%p\n", (void*)(g->stacklo), (void*)(g->stackhi));
+		abort();
+	}
+
+	pthread_attr_destroy(pattr);
+}
+
 // Store the g into a thread-specific value associated with the pthread key pthread_g.
 // And pthread_key_destructor will dropm when the thread is exiting.
 void x_cgo_bindm(void* g) {

src/runtime/cgo/gcc_linux_386.c

@@ -17,14 +17,8 @@ void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_amd64.c

@@ -20,7 +20,6 @@ void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
 	pthread_attr_t *attr;
-	size_t size;
 
 	/* The memory sanitizer distributed with versions of clang
 	   before 3.8 has a bug: if you call mmap before malloc, mmap
@@ -42,12 +41,7 @@ x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 	if (attr == NULL) {
 		fatalf("malloc failed: %s", strerror(errno));
 	}
-	pthread_attr_init(attr);
-	pthread_attr_getstacksize(attr, &size);
-	g->stacklo = (uintptr)__builtin_frame_address(0) - size + 4096;
-	if (g->stacklo >= g->stackhi)
-		fatalf("bad stack bounds: lo=%p hi=%p\n", g->stacklo, g->stackhi);
-	pthread_attr_destroy(attr);
+	_cgo_set_stacklo(g, attr);
 	free(attr);
 
 	if (x_cgo_inittls) {

src/runtime/cgo/gcc_linux_arm.c

@@ -54,14 +54,8 @@ threadentry(void *v)
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_arm64.c

@@ -57,7 +57,6 @@ void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
 	pthread_attr_t *attr;
-	size_t size;
 
 	/* The memory sanitizer distributed with versions of clang
 	   before 3.8 has a bug: if you call mmap before malloc, mmap
@@ -79,10 +78,7 @@ x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 	if (attr == NULL) {
 		fatalf("malloc failed: %s", strerror(errno));
 	}
-	pthread_attr_init(attr);
-	pthread_attr_getstacksize(attr, &size);
-	g->stacklo = (uintptr)&size - size + 4096;
-	pthread_attr_destroy(attr);
+	_cgo_set_stacklo(g, attr);
 	free(attr);
 
 	if (x_cgo_inittls) {

src/runtime/cgo/gcc_linux_loong64.c

@@ -54,14 +54,8 @@ threadentry(void *v)
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_mips64x.c

@@ -56,14 +56,8 @@ threadentry(void *v)
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_mipsx.c

@@ -56,15 +56,9 @@ threadentry(void *v)
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
 
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_riscv64.c

@@ -54,14 +54,8 @@ threadentry(void *v)
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 
 	if (x_cgo_inittls) {
 		x_cgo_inittls(tlsg, tlsbase);

src/runtime/cgo/gcc_linux_s390x.c

@@ -16,14 +16,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_netbsd_386.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_netbsd_amd64.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_netbsd_arm.c

@@ -16,14 +16,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_netbsd_arm64.c

@@ -16,14 +16,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 

src/runtime/cgo/gcc_openbsd_386.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_openbsd_amd64.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_openbsd_arm.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_openbsd_arm64.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_openbsd_mips64.c

@@ -15,14 +15,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*))
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_ppc64x.c

@@ -18,14 +18,8 @@ static void (*setg_gcc)(void*);
 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsbase)
 {
-	pthread_attr_t attr;
-	size_t size;
-
 	setg_gcc = setg;
-	pthread_attr_init(&attr);
-	pthread_attr_getstacksize(&attr, &size);
-	g->stacklo = (uintptr)&attr - size + 4096;
-	pthread_attr_destroy(&attr);
+	_cgo_set_stacklo(g, NULL);
 }
 
 void

src/runtime/cgo/gcc_solaris_amd64.c

@@ -27,6 +27,13 @@ x_cgo_init(G *g, void (*setg)(void*))
 	// See golang.org/issue/12210.
 	if(ctx.uc_stack.ss_size < 1024*1024)
 		g->stacklo -= 1024*1024 - ctx.uc_stack.ss_size;
+
+	// Sanity check the results now, rather than getting a
+	// morestack on g0 crash.
+	if (g->stacklo >= g->stackhi) {
+		fprintf(stderr, "runtime/cgo: bad stack bounds: lo=%p hi=%p\n", (void*)(g->stacklo), (void*)(g->stackhi));
+		abort();
+	}
 }
 
 void

src/runtime/cgo/libcgo_unix.h

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+/*
+ * Initialize g->stacklo.
+ */
+extern void _cgo_set_stacklo(G *, pthread_attr_t*);
+
 /*
  * Call pthread_create, retrying on EAGAIN.
  */