From b21d3535a53d03578705f5458c02afc37922d39f Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Mon, 23 Mar 2020 20:12:10 +0100
Subject: [PATCH] std: Fix parameters for pthread_attr_setstack

The guard page size shouldn't be taken into account, pthread is only
interested in the usable area.
---
 lib/std/thread.zig | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/std/thread.zig b/lib/std/thread.zig
index 4b28d7cf6d..f2b27caa97 100644
--- a/lib/std/thread.zig
+++ b/lib/std/thread.zig
@@ -375,7 +375,12 @@ pub const Thread = struct {
             if (c.pthread_attr_init(&attr) != 0) return error.SystemResources;
             defer assert(c.pthread_attr_destroy(&attr) == 0);
 
-            assert(c.pthread_attr_setstack(&attr, mmap_slice.ptr, stack_end_offset) == 0);
+            // Tell pthread where the effective stack start is and its size
+            assert(c.pthread_attr_setstack(
+                &attr,
+                mmap_slice.ptr + guard_end_offset,
+                stack_end_offset - guard_end_offset,
+            ) == 0);
 
             const err = c.pthread_create(&thread_ptr.data.handle, &attr, MainFuncs.posixThreadMain, @intToPtr(*c_void, arg));
             switch (err) {