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Date:   Mon, 6 Jan 2020 09:23:15 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     KP Singh <kpsingh@chromium.org>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org,
        linux-security-module@vger.kernel.org,
        Kees Cook <keescook@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andriin@fb.com>,
        Thomas Garnier <thgarnie@chromium.org>,
        Florent Revest <revest@chromium.org>,
        Brendan Jackman <jackmanb@chromium.org>,
        Jann Horn <jannh@google.com>,
        Matthew Garrett <mjg59@google.com>,
        Michael Halcrow <mhalcrow@google.com>
Subject: Re: [PATCH bpf-next] bpf: Make trampolines W^X
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On Sat, Jan 04, 2020 at 09:49:10AM +0900, Andy Lutomirski wrote:

> > - Mark memory as non executable (set_memory_nx). While module_alloc for
> > x86 allocates the memory as PAGE_KERNEL and not PAGE_KERNEL_EXEC, not
> > all implementations of module_alloc do so
> 
> How about fixing this instead?

We only care about STRICT_MODULE_RMW (iow, arm, arm64, s390, x86). Of
those only s390 seems to be 'off'.