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Date:   Wed, 28 Jul 2021 16:34:55 -0500
From:   John Allen <john.allen@amd.com>
To:     "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Cc:     Florian Weimer <fweimer@redhat.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-mm@kvack.org,
        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
        Andy Lutomirski <luto@kernel.org>,
        Balbir Singh <bsingharora@gmail.com>,
        Borislav Petkov <bp@alien8.de>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Eugene Syromiatnikov <esyr@redhat.com>,
        "H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
        Dave Martin <Dave.Martin@arm.com>,
        Weijiang Yang <weijiang.yang@intel.com>,
        Pengfei Xu <pengfei.xu@intel.com>,
        Haitao Huang <haitao.huang@intel.com>,
        "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Subject: Re: [PATCH v27 24/31] x86/cet/shstk: Handle thread shadow stack
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On Wed, Jul 21, 2021 at 11:34:53AM -0700, Yu, Yu-cheng wrote:
> On 7/21/2021 11:28 AM, Florian Weimer wrote:
> > I expect that container runtimes turn clone3 into clone in the same way
> > (via ENOSYS), at least for the medium term.  So it would make sense to
> > allocate some sort of shadow stack for clone as well, if that's possible
> > to implement in some way.
> > 
> > Thanks,
> > Florian
> > 
> 
> Thanks Florian!  And because of that reason, we will put back clone2 support
> in my next v28 patches.
> 
> Yu-cheng

I tested with v28 of the patches on the same system and it appears to
fix the issue I was seeing.

Thanks,
John