Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
Message-ID: <63dd7222-99dc-8e11-3a51-b132e4115ac5@linuxfoundation.org>
Date:   Tue, 26 Sep 2023 14:39:27 -0600
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.15.1
Subject: Re: [PATCH] selftests/rseq: fix kselftest Clang build warnings
Content-Language: en-US
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Justin Stitt <justinstitt@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        Shuah Khan <shuah@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        llvm@lists.linux.dev, Shuah Khan <skhan@linuxfoundation.org>
References: <20230912-kselftest-param_test-c-v1-1-80a6cffc7374@google.com>
 <CAFhGd8on9_DJUZqT5uKgPzOtJNn99sY3TprcPzD5pm3GmYx8oQ@mail.gmail.com>
 <eabe9db0-c934-af2d-e5a9-9d644593851c@efficios.com>
From:   Shuah Khan <skhan@linuxfoundation.org>
In-Reply-To: <eabe9db0-c934-af2d-e5a9-9d644593851c@efficios.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 9/26/23 13:02, Mathieu Desnoyers wrote:
> On 9/26/23 08:20, Justin Stitt wrote:
>> Ping.
>>
>> Looking to get this patch and [1] slated for 6.7 which fixes some
>> kselftest builds on older kernels.
>>
>> On Wed, Sep 13, 2023 at 6:03 AM Justin Stitt <justinstitt@google.com> wrote:
>>>
>>> When building with Clang, I am getting many warnings from the selftests/rseq tree.
>>>
>>> Here's one such example from rseq tree:
>>> |  param_test.c:1234:10: error: address argument to atomic operation must be a pointer to _Atomic type ('intptr_t *' (aka 'long *') invalid)
>>> |   1234 |         while (!atomic_load(&args->percpu_list_ptr)) {}
>>> |        |                 ^           ~~~~~~~~~~~~~~~~~~~~~~
>>> |  /usr/local/google/home/justinstitt/repos/tc-build/build/llvm/final/lib/clang/18/include/stdatomic.h:140:29: note: expanded from macro 'atomic_load'
>>> |    140 | #define atomic_load(object) __c11_atomic_load(object, __ATOMIC_SEQ_CST)
>>> |        |                             ^                 ~~~~~~
>>>
>>> Use compiler builtins `__atomic_load_n()` and `__atomic_store_n()` with
>>> accompanying __ATOMIC_ACQUIRE and __ATOMIC_RELEASE, respectively. This
>>> will fix the warnings because the compiler builtins do not expect their
>>> arguments to have _Atomic type. This should also make TSAN happier.
>>>
>>> Link: https://github.com/ClangBuiltLinux/linux/issues/1698
>>> Link: https://github.com/ClangBuiltLinux/continuous-integration2/issues/61
>>> Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>>> Signed-off-by: Justin Stitt <justinstitt@google.com>
> 
> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> 
> Peter, should this go through tip ?
> 
> Shuah, should to go through selftests ?
> 

I can take this through selftests and apply it - hoping there
are no conflicts with what's in Peter's tree.

thanks,
-- Shuah