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From:   SS JieJi <c141028@gmail.com>
Date:   Fri, 9 Sep 2022 01:28:24 +0800
Message-ID: <CANaf2scD5QtgZuAXru5=uaZOkAQ_seHbJO0YKmT07DCTDLwKQw@mail.gmail.com>
Subject: Re: [PATCH] riscv: Allow PROT_WRITE-only mmap()
To:     Andrew Bresticker <abrestic@rivosinc.com>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Atish Patra <atishp@atishpatra.org>,
        Celeste Liu <coelacanthus@outlook.com>,
        dram <dramforever@live.com>, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org
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> https://fars.ee/1sPb, showing *inconsistent* read results on -r- pages
> before/after a write attempt performed by the kernel.

That said, maybe prohibit mmap-ing -w- pages is not the best fix for
this issue. If -w- pages are irreplaceable for some use cases (and
hence need to be allowed), I'd suggest at least we need to re-fix the
read result inconsistency issue somewhere else despite simply
reverting the patch.

Yours, Pan Ruizhe