[patch] 0001-powerpc-disable-calculation-of-caller-address-in-mal.patch

0001-powerpc-disable-calculation-of-caller-address-in-mal.patch (text/plain), 1.38 KB, created by Sergei Trofimovich (RETIRED) on 2017-08-27 15:04:09 UTC

From 23fff6dd8787e3059146ebda480e74667519b6eb Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <[e-mail]>
Date: Sun, 27 Aug 2017 15:57:37 +0100
Subject: [PATCH] powerpc: disable calculation of caller address in malloc
 hooks

At least on powerpc-unknown-linux-gnu the code
    __builtin_return_address(0)
generates memory access to uninitialized stack
in -fPIC -fstack-protector-all mode.
This mode is default for gcc-6.3+/glibc-2.25+ in Gentoo.

Workaround the problem by disabling return address calculation.
Default glibc hooks don't use passed address at all.

Bug: https://bugs.gentoo.org/629054
Bug: https://gcc.gnu.org/PR81996
Bug: https://sourceware.org/PR22016
Signed-off-by: Sergei Trofimovich <[e-mail]>
---
 malloc/malloc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index e3ff778113..85848dce0a 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -995,6 +995,16 @@ int      __posix_memalign(void **, size_t, size_t);
 
 #include <malloc.h>
 
+#ifdef __powerpc__
+/* On 32-bit powerpc gcc genrates incorrect core for
+ * __builtin_return_address in -fstack-protector-all
+ * mode. See https://bugs.gentoo.org/629054 for details.
+ *
+ * As a workaround sdsable resolution of return addresses
+ * in malloc hooks.
+ */
+#undef RETURN_ADDRESS
+#endif
 #ifndef RETURN_ADDRESS
 #define RETURN_ADDRESS(X_) (NULL)
 #endif
-- 
2.14.1