Add NEWS entry about the change in handling of PT_GNU_STACK on MIPS

The change was introduced in:

commit 33bc9efd91
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.

Co-authored-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
Dragan Mladjenovic 2020-01-22 17:14:23 +00:00 committed by Siddhesh Poyarekar
parent d937694059
commit ba44e5b508

12
NEWS
View File

@ -112,6 +112,18 @@ Deprecated and removed features, and other changes affecting compatibility:
captured in a dlerror message. In general, this is unsafe because captured in a dlerror message. In general, this is unsafe because
resetting the stack in an arbitrary function call is not possible. resetting the stack in an arbitrary function call is not possible.
* For MIPS hard-float ABIs, the GNU C Library will be configured to need an
executable stack unless explicitly configured at build time to require
minimum kernel version 4.8 or newer. This is because executing
floating-point branches on a non-executable stack on Linux kernels prior to
4.8 can lead to application crashes for some MIPS configurations. While
currently PT_GNU_STACK is not widely used on MIPS, future releases of GCC are
expected to enable non-executable stack by default with PT_GNU_STACK by
default and is thus likely to trigger a crash on older kernels.
The GNU C Library can be built with --enable-kernel=4.8.0 in order to keep a
non-executable stack while dropping support for older kernels.
Changes to build and runtime requirements: Changes to build and runtime requirements:
* It is no longer necessary to have recent Linux kernel headers to build * It is no longer necessary to have recent Linux kernel headers to build