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References: <20220301075839.4156-2-xiam0nd.tong@gmail.com> <202203020135.5duGpXM2-lkp@intel.com>
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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 1 Mar 2022 12:16:28 -0800
Message-ID: <CAHk-=wiVF0SeV2132vaTAcL1ccVDP25LkAgNgPoHXdFc27x-0g@mail.gmail.com>
Subject: Re: [PATCH 1/6] Kbuild: compile kernel with gnu11 std
To:     kernel test robot <lkp@intel.com>
Cc:     Xiaomeng Tong <xiam0nd.tong@gmail.com>, kbuild-all@lists.01.org,
        Arnd Bergmann <arnd@arndb.de>,
        Jakob Koschel <jakobkoschel@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kees Cook <keescook@chromium.org>,
        Jann Horn <jannh@google.com>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>, Netdev <netdev@vger.kernel.org>
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On Tue, Mar 1, 2022 at 10:00 AM kernel test robot <lkp@intel.com> wrote:
>
> All warnings (new ones prefixed by >>):
>
> >> cc1: warning: result of '-117440512 << 16' requires 44 bits to represent, but 'int' only has 32 bits [-Wshift-overflow=]

So that's potentially an interesting warning, but this email doesn't
actually tell *where* that warning happens.

I'm not entirely sure why this warning is new to this '-std=gnu11'
change, but it's intriguing.

Instead it then gives the location for another warning:

>    arch/mips/pci/pci-rc32434.c: In function 'rc32434_pcibridge_init':
>    arch/mips/pci/pci-rc32434.c:111:22: warning: variable 'dummyread' set but not used [-Wunused-but-set-variable]
>      111 |         unsigned int dummyread, pcicntlval;
>          |                      ^~~~~~~~~

but that wasn't the new one (and that 'dummyread' is obviously
_intentionally_ set but not used, as implied by the name).

Is there some place to actually see the full log (or some way to get a
better pointer to just the new warning) to see that actual shift
overflow thing?

              Linus