On Wed, Apr 29, 2020 at 03:44:19PM -0400, Daniele Buono wrote:
> This patch adds a flag to enable the SafeStack instrumentation provided
> by LLVM.
> The checks make sure that the compiler supports the flags, and that we
> are using the proper coroutine implementation (coroutine-ucontext).
> While SafeStack is supported only on Linux, NetBSD, FreeBSD and macOS,
> we are not checking for the O.S. since this is already done by LLVM.
> 
> Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
> ---
>  configure | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)

Great, this can become Patch 1 and it can set CONFIG_SAFESTACK as
mentioned in my earlier reply.

> diff --git a/configure b/configure
> index 23b5e93752..f37e4ae0bd 100755
> --- a/configure
> +++ b/configure
> @@ -302,6 +302,7 @@ audio_win_int=""
>  libs_qga=""
>  debug_info="yes"
>  stack_protector=""
> +safe_stack="no"

The comment above this says:

  # Always add --enable-foo and --disable-foo command line args.

Please add --disable-safe-stack.