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[PATCH] Add NEWS entry about the change in handling of PT_GNU_STACK on MIPS
- From: Dragan Mladjenovic <dmladjenovic at wavecomp dot com>
- To: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Cc: Dragan Mladjenovic <dmladjenovic at wavecomp dot com>, Joseph Myers <joseph at codesourcery dot com>, Siddhesh Poyarekar <siddhesh at sourceware dot org>
- Date: Wed, 22 Jan 2020 17:14:23 +0000
- Subject: [PATCH] Add NEWS entry about the change in handling of PT_GNU_STACK on MIPS
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From: "Dragan Mladjenovic" <dmladjenovic@wavecomp.com>
The change was introduced in:
commit 33bc9efd91de1b14354291fc8ebd5bce96379f12
Author: Dragan Mladjenovic <dmladjenovic@wavecomp.com>
Date: Fri Aug 23 16:38:04 2019 +0000
mips: Force RWX stack for hard-float builds that can run on pre-4.8 kernels
and probably requires a small explanation.
---
NEWS | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/NEWS b/NEWS
index 44065d9..1e5dcf3 100644
--- a/NEWS
+++ b/NEWS
@@ -112,6 +112,18 @@ Deprecated and removed features, and other changes affecting compatibility:
captured in a dlerror message. In general, this is unsafe because
resetting the stack in an arbitrary function call is not possible.
+* For the MIPS hard-float ABIs, the glibc will no longer honor RW PT_GNU_STACK
+ and will run on executable stack unless explicitly configured at build time
+ to require minimum kernel version 4.8 or newer. On Linux kernels prior to
+ 4.8 executing floating-point branches on non-executable stack can
+ lead to application crashes for some MIPS configurations. While currently
+ the PT_GNU_STACK is not widely used on MIPS, the future releases of GCC are
+ expected to enable RW PT_GNU_STACK by default thus likely to trigger the
+ crash on older kernels.
+
+ The glibc can be built with --enable-kernel=4.8.0 in order to honor
+ RW PT_GNU_STACK while dropping support for older kernels.
+
Changes to build and runtime requirements:
* It is no longer necessary to have recent Linux kernel headers to build
--
1.9.1