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Date:   Thu, 21 Oct 2021 09:09:42 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 07/20] signal/powerpc: On swapcontext failure force
 SIGSEGV
Message-ID: <202110210909.895B8A5A58@keescook>
References: <87y26nmwkb.fsf@disp2133>
 <20211020174406.17889-7-ebiederm@xmission.com>
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On Wed, Oct 20, 2021 at 12:43:53PM -0500, Eric W. Biederman wrote:
> If the register state may be partial and corrupted instead of calling
> do_exit, call force_sigsegv(SIGSEGV).  Which properly kills the
> process with SIGSEGV and does not let any more userspace code execute,
> instead of just killing one thread of the process and potentially
> confusing everything.
> 
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: linuxppc-dev@lists.ozlabs.org
> History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
> Fixes: 756f1ae8a44e ("PPC32: Rework signal code and add a swapcontext system call.")
> Fixes: 04879b04bf50 ("[PATCH] ppc64: VMX (Altivec) support & signal32 rework, from Ben Herrenschmidt")
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

This looks right to me.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook