From 0dd86764f0e6c25e6f6e6f38c72c35f4d34d6988 Mon Sep 17 00:00:00 2001
From: "A. Wilcox" <AWilcox@Wilcox-Tech.com>
Date: Sun, 25 Dec 2022 01:49:26 -0600
Subject: system/gcc: Ensure gccgo doesn't run off the stack

libucontext doesn't clear the stack frame below makecontext.  This
caused us to end up crashing like Solaris[1].

Fixes: #832

[1]: https://gcc.gnu.org/PR52583#c21
---
 system/gcc/341-gccgo-libucontext-stack.patch | 18 ++++++++++++++++++
 system/gcc/APKBUILD                          |  2 ++
 2 files changed, 20 insertions(+)
 create mode 100644 system/gcc/341-gccgo-libucontext-stack.patch

(limited to 'system')

diff --git a/system/gcc/341-gccgo-libucontext-stack.patch b/system/gcc/341-gccgo-libucontext-stack.patch
new file mode 100644
index 000000000..2befc5d32
--- /dev/null
+++ b/system/gcc/341-gccgo-libucontext-stack.patch
@@ -0,0 +1,18 @@
+Similar to Solaris, libucontext does not clear the stack below makecontext.
+This causes the Go frontend to sometimes go below the stack.
+
+On 32-bit Arm systems, this resulted in #832.  It is likely, though not known,
+that this could have caused other issues we've seen in gccgo as well.
+
+--- gcc-8.5.0/libgo/runtime/go-callers.c.old	2021-05-14 03:42:11.000000000 -0500
++++ gcc-8.5.0/libgo/runtime/go-callers.c	2022-12-25 01:46:15.834110528 -0600
+@@ -117,7 +117,8 @@
+      Solaris (http://gcc.gnu.org/PR52583 comment #21).  */
+   if (function != NULL)
+     {
+-      if (__builtin_strcmp (function, "makecontext") == 0)
++      if (__builtin_strcmp (function, "makecontext") == 0
++          || __builtin_strcmp (function, "libucontext_makecontext") == 0)
+ 	return 1;
+       if (filename != NULL)
+ 	{
diff --git a/system/gcc/APKBUILD b/system/gcc/APKBUILD
index ff4649fb9..6ce9887b6 100644
--- a/system/gcc/APKBUILD
+++ b/system/gcc/APKBUILD
@@ -181,6 +181,7 @@ source="https://ftp.gnu.org/gnu/gcc/gcc-$pkgver/gcc-$pkgver.tar.xz
 	338-gccgo-syscall.patch
 	339-gccgo-errstr.patch
 	340-gccgo-time64-stat.patch
+	341-gccgo-libucontext-stack.patch
 
 	add-classic_table-support.patch
 	gcc-5.4.0-locale.patch
@@ -580,6 +581,7 @@ c2916948b028e1e990e1953875b884561c0f8dd105c1ec03073795df9a47ec2c627cbc95ca0ec98a
 0bdf592ec8444c6e253f1a7626b4e618b2e18e6d0b5a4548f90903f9de80a7cf3ea536750c2743f436a05faa1e7b65e52a391da9732dce51c4b00e23853e5365  338-gccgo-syscall.patch
 b32d496a3a04c2357200b75dbf7f667fb57bf5af4f0c68926bc58f6600e4f23caa48aad2eaf073f1408168cacf27e8f11a6062c65bf5bb67458eedef698871d4  339-gccgo-errstr.patch
 4db4a00dff1d3cb3ecbc713659316782ac839478ff1fd7166cfa64a2c7cee0ba2a0d3fa23cb858af7d8f59a6ac2bdf40e63a45c307b89eefe2a4e888707f615b  340-gccgo-time64-stat.patch
+71ee2ce239c62bedc90d0688a40e3e381e641ba9e322c6319c2f6a4362c17d60a232dcb32fd08f5ff9ed5c058c0a010362197839cb391d85bc4a6446943ad4b2  341-gccgo-libucontext-stack.patch
 1860593584f629d24d5b6db14b0a3412e9f93449b663aaa4981301a0923db0159314905e694f27366fbfef72dce06636ab6df86862b7e9e9564847e03bee82c1  add-classic_table-support.patch
 67a75a94fdba69de96b98dbc2978a50cb197857c464b81f7c956176da7066b3be937e40cb15e0870fc1e7382d662c5101bcd18cf457fc4112de41802042b51c4  gcc-5.4.0-locale.patch
 65a4d8bf9cefcbc79e86015ef4376b2794492d6cae77065359b35bb4ed630dde6256982cd5e43ed837cbbdab366ea376da9f1c83f80ddf6dc53ab017b378c3cd  backport-r267157-posix-conformant-snprintf.patch
-- 
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