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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 29 Jun 2018 07:17:52 -0700
Message-ID: <CA+55aFxRJWjbgLeSQ_swi3F5nF1SYgZnC-R7QsOvZdcuSaWeaw@mail.gmail.com>
Subject: Re: [RFC PATCH for 4.18 1/2] rseq: validate rseq_cs fields are < TASK_SIZE
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     Andy Lutomirski <luto@amacapital.net>,
        Andrew Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King - ARM Linux <linux@arm.linux.org.uk>,
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On Fri, Jun 29, 2018 at 7:05 AM Mathieu Desnoyers
<mathieu.desnoyers@efficios.com> wrote:
>
> What I'm worried about is setting regs->ip of a compat 32-bit task to
> addresses in the range 0x100000000-0xFFFFFFFFFFFFFFFF.

Well, they won't have anything mapped in that range, so it really
shouldn't matter.

                 Linus