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References: <20211207122448.1185769-1-arnd@kernel.org>
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From:   Todd Kjos <tkjos@google.com>
Date:   Tue, 7 Dec 2021 08:51:28 -0800
Message-ID: <CAHRSSEyuWLHWyxnmes=Kd6vwXrm+_UHb7etgKT1kfdTeV0RqVA@mail.gmail.com>
Subject: Re: [PATCH] binder: fix pointer cast warning
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Christian Brauner <christian@brauner.io>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Arnd Bergmann <arnd@arndb.de>, Li Li <dualli@google.com>,
        Marco Ballesio <balejs@google.com>,
        Hang Lu <hangl@codeaurora.org>, linux-kernel@vger.kernel.org
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On Tue, Dec 7, 2021 at 4:25 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> binder_uintptr_t is not the same as uintptr_t, so converting it into a
> pointer requires a second cast:
>
> drivers/android/binder.c: In function 'binder_translate_fd_array':
> drivers/android/binder.c:2511:28: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>  2511 |         sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
>       |                            ^
>
> Fixes: 656e01f3ab54 ("binder: read pre-translated fds from sender buffer")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Todd Kjos <tkjos@google.com>

> ---
>  drivers/android/binder.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 5497797ab258..182bb4221b06 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2508,7 +2508,8 @@ static int binder_translate_fd_array(struct list_head *pf_head,
>          */
>         fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
>                 fda->parent_offset;
> -       sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
> +       sender_ufda_base = (void __user *)(uintptr_t)sender_uparent->buffer +
> +                               fda->parent_offset;
>
>         if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32)) ||
>             !IS_ALIGNED((unsigned long)sender_ufda_base, sizeof(u32))) {
> --
> 2.29.2
>