linux-kernel - Re: [PATCH v2 05/28] objtool: Add a pass for generating __mcount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CABCJKueF1RbpOKHsA8yS_yMujzHi8dzAVz8APwpMJyMTTGhmDA@mail.gmail.com>
Date:   Thu, 3 Sep 2020 15:03:30 -0700
From:   Sami Tolvanen <samitolvanen@...gle.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     Masahiro Yamada <masahiroy@...nel.org>,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kbuild <linux-kbuild@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org,
        X86 ML <x86@...nel.org>
Subject: Re: [PATCH v2 05/28] objtool: Add a pass for generating __mcount_loc

On Thu, Sep 3, 2020 at 2:51 PM Kees Cook <keescook@...omium.org> wrote:
>
> On Thu, Sep 03, 2020 at 01:30:30PM -0700, Sami Tolvanen wrote:
> > From: Peter Zijlstra <peterz@...radead.org>
> >
> > Add the --mcount option for generating __mcount_loc sections
> > needed for dynamic ftrace. Using this pass requires the kernel to
> > be compiled with -mfentry and CC_USING_NOP_MCOUNT to be defined
> > in Makefile.
> >
> > Link: https://lore.kernel.org/lkml/20200625200235.GQ4781@hirez.programming.kicks-ass.net/
> > Signed-off-by: Peter Zijlstra <peterz@...radead.org>
>
> Hmm, I'm not sure why this hasn't gotten picked up yet. Is this expected
> to go through -tip or something else?

Note that I picked up this patch from Peter's original email, to which
I included a link in the commit message, but it wasn't officially
submitted as a patch. However, the previous discussion seems to have
died, so I included the patch in this series, as it cleanly solves the
problem of whitelisting non-call references to __fentry__. I was
hoping for Peter and Steven to comment on how they prefer to proceed
here.

Sami