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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 28 May 2018 11:19:55 +0200
Message-ID: <CAMuHMdXxL+k_SitLXV1LJDHJmCY1HiUnZSk7MM64rcgs75nLiw@mail.gmail.com>
Subject: Re: [REVIEW][PATCH 16/22] signal/sh: Use force_sig_fault where appropriate
To:     Rich Felker <dalias@libc.org>
Cc:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Linux-sh list <linux-sh@vger.kernel.org>
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On Fri, Apr 20, 2018 at 4:55 PM, Rich Felker <dalias@libc.org> wrote:
> On Fri, Apr 20, 2018 at 09:38:05AM -0500, Eric W. Biederman wrote:
>> Filling in struct siginfo before calling force_sig_info a tedious and
>> error prone process, where once in a great while the wrong fields
>> are filled out, and siginfo has been inconsistently cleared.
>>
>> Simplify this process by using the helper force_sig_fault.  Which
>> takes as a parameters all of the information it needs, ensures
>> all of the fiddly bits of filling in struct siginfo are done properly
>> and then calls force_sig_info.
>>
>> In short about a 5 line reduction in code for every time force_sig_info
>> is called, which makes the calling function clearer.
>>
>> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
>> Cc: Rich Felker <dalias@libc.org>
>> Cc: linux-sh@vger.kernel.org
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

>> --- a/arch/sh/kernel/traps_32.c
>> +++ b/arch/sh/kernel/traps_32.c

>> @@ -599,20 +593,17 @@ int is_dsp_inst(struct pt_regs *regs)
>>  #ifdef CONFIG_CPU_SH2A
>>  asmlinkage void do_divide_error(unsigned long r4)
>>  {
>> -     siginfo_t info;
>> +     int code;
>>
>> -     clear_siginfo(&info);
>>       switch (r4) {
>>       case TRAP_DIVZERO_ERROR:
>> -             info.si_code = FPE_INTDIV;
>> +             code = FPE_INTDIV;
>>               break;
>>       case TRAP_DIVOVF_ERROR:
>> -             info.si_code = FPE_INTOVF;
>> +             code = FPE_INTOVF;
>>               break;
>>       }
>> -
>> -     info.si_signo = SIGFPE;
>> -     force_sig_info(info.si_signo, &info, current);
>> +     force_sig_fault(SIGFPE, code, NULL, current);

/kisskb/src/arch/sh/kernel/traps_32.c:606:17: error: 'code' may be
used uninitialized in this function [-Werror=uninitialized]

http://kisskb.ellerman.id.au/kisskb/buildresult/13366052/
http://kisskb.ellerman.id.au/kisskb/buildresult/13366048/
http://kisskb.ellerman.id.au/kisskb/buildresult/13366072/

>>  }

> Acked-by: Rich Felker <dalias@libc.org>


Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds