LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Rong Chen <rong.a.chen@intel.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
	kernel test robot <lkp@intel.com>
Cc: clang-built-linux@googlegroups.com, kbuild-all@lists.01.org,
	linux-kernel@vger.kernel.org,
	Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [kbuild-all] Re: arch/powerpc/kernel/signal_32.c:297:2: warning: Value stored to 'msr' is never read [clang-analyzer-deadcode.DeadStores]
Date: Wed, 25 Aug 2021 16:48:23 +0800	[thread overview]
Message-ID: <6e7edeb5-07fc-fedc-7f9c-0e2eb23e22bb@intel.com> (raw)
In-Reply-To: <79754a11-fa14-756a-fc30-5cb139a286b6@csgroup.eu>



On 8/24/21 3:29 PM, Christophe Leroy wrote:
>
>
> Le 24/08/2021 à 08:59, Chen, Rong A a écrit :
>>
>>
>> On 8/23/2021 10:35 PM, Christophe Leroy wrote:
>>>
>>>
>>> Le 23/08/2021 à 12:59, kernel test robot a écrit :
>>>> tree: 
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
>>>> master
>>>> head:   e22ce8eb631bdc47a4a4ea7ecf4e4ba499db4f93
>>>> commit: ef75e73182949a94bde169a774de1b62ae21fbbc powerpc/signal32: 
>>>> Transform save_user_regs() and save_tm_user_regs() in 'unsafe' version
>>>> date:   9 months ago
>>>> config: powerpc-randconfig-c003-20210821 (attached as .config)
>>>> compiler: clang version 14.0.0 
>>>> (https://github.com/llvm/llvm-project 
>>>> d9c5613e856cf2addfbf892fc4c1ce9ef9feceaa)
>>>> reproduce (this is a W=1 build):
>>>>          wget 
>>>> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross 
>>>> -O ~/bin/make.cross
>>>>          chmod +x ~/bin/make.cross
>>>>          # install powerpc cross compiling tool for clang build
>>>>          # apt-get install binutils-powerpc-linux-gnu
>>>>          # 
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ef75e73182949a94bde169a774de1b62ae21fbbc 
>>>>
>>>>          git remote add linus 
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>>          git fetch --no-tags linus master
>>>>          git checkout ef75e73182949a94bde169a774de1b62ae21fbbc
>>>>          # save the attached .config to linux build tree
>>>>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 
>>>> ARCH=powerpc clang-analyzer
>>>>
>>>> If you fix the issue, kindly add following tag as appropriate
>>>> Reported-by: kernel test robot <lkp@intel.com>
>>>>
>>>>
>>>> clang-analyzer warnings: (new ones prefixed by >>)
>>>>             ^
>>>>>> arch/powerpc/kernel/signal_32.c:297:2: warning: Value stored to 
>>>>>> 'msr' is never read [clang-analyzer-deadcode.DeadStores]
>>>>             msr &= ~MSR_VSX;
>>>>             ^      ~~~~~~~~
>>>>     arch/powerpc/kernel/signal_32.c:297:2: note: Value stored to 
>>>> 'msr' is never read
>>>>             msr &= ~MSR_VSX;
>>>>             ^      ~~~~~~~~
>>>
>>>
>>> This is wrong.
>>>
>>> msr is used at line 326:
>>>
>>> ef75e73182949a arch/powerpc/kernel/signal_32.c Christophe Leroy 
>>> 2020-08-18  326 unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed);
>>
>> Hi Christophe,
>>
>> The usage is under CONFIG_VSX, the test config 
>> (powerpc-randconfig-c003-20210821) didn't enable it which triggered 
>> this warning.
>
>
> No no, the 'unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed) ' 
> at line 326 is not under CONFIG_VSX as far as I can see.
>
>
> Christophe

Hi Christophe,

It's my fault, I didn't see it correctly, and I have no idea why 
clang-analyzer reported it as a issue,
we'll double check such warning next time.

Best Regards,
Rong Chen

      reply	other threads:[~2021-08-25  8:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-23 10:59 kernel test robot
2021-08-23 14:35 ` Christophe Leroy
2021-08-24  6:59   ` [kbuild-all] " Chen, Rong A
2021-08-24  7:29     ` Christophe Leroy
2021-08-25  8:48       ` Rong Chen [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6e7edeb5-07fc-fedc-7f9c-0e2eb23e22bb@intel.com \
    --to=rong.a.chen@intel.com \
    --cc=christophe.leroy@csgroup.eu \
    --cc=clang-built-linux@googlegroups.com \
    --cc=kbuild-all@lists.01.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lkp@intel.com \
    --cc=mpe@ellerman.id.au \
    --subject='Re: [kbuild-all] Re: arch/powerpc/kernel/signal_32.c:297:2: warning: Value stored to '\''msr'\'' is never read [clang-analyzer-deadcode.DeadStores]' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).