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References: <cover.1676063693.git.andreyknvl@google.com> <359ac9c13cd0869c56740fb2029f505e41593830.1676063693.git.andreyknvl@google.com>
In-Reply-To: <359ac9c13cd0869c56740fb2029f505e41593830.1676063693.git.andreyknvl@google.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Mon, 13 Feb 2023 12:52:12 +0100
Message-ID: <CAG_fn=WTXE67+zPc7frp7sPvJ82G+GCJe-0+Uz+nN4PUP7+uag@mail.gmail.com>
Subject: Re: [PATCH v2 16/18] lib/stackdepot: annotate racy pool_index accesses
To:     andrey.konovalov@linux.dev
Cc:     Marco Elver <elver@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        Evgenii Stepanov <eugenis@google.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
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On Fri, Feb 10, 2023 at 10:18 PM <andrey.konovalov@linux.dev> wrote:
>
> From: Andrey Konovalov <andreyknvl@google.com>
>
> Accesses to pool_index are protected by pool_lock everywhere except
> in a sanity check in stack_depot_fetch. The read access there can race
> with the write access in depot_alloc_stack.
>
> Use WRITE/READ_ONCE() to annotate the racy accesses.
>
> As the sanity check is only used to print a warning in case of a
> violation of the stack depot interface usage, it does not make a lot
> of sense to use proper synchronization.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>