linux-kernel - Re: [PATCH] erofs: Eliminate usage of uninitialized

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Date:   Mon, 15 Jun 2020 15:43:09 +0800
From:   Jason Yan <yanaijie@...wei.com>
To:     Gao Xiang <hsiangkao@...hat.com>
CC:     <xiang@...nel.org>, <chao@...nel.org>,
        <gregkh@...uxfoundation.org>, <linux-erofs@...ts.ozlabs.org>,
        <linux-kernel@...r.kernel.org>, Kees Cook <keescook@...omium.org>,
        <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH] erofs: Eliminate usage of uninitialized_var() macro



在 2020/6/15 15:25, Gao Xiang 写道:
> Hi Jason,
> 
> On Mon, Jun 15, 2020 at 12:01:41PM +0800, Jason Yan wrote:
>> This is an effort to eliminate the uninitialized_var() macro[1].
>>
>> The use of this macro is the wrong solution because it forces off ANY
>> analysis by the compiler for a given variable. It even masks "unused
>> variable" warnings.
>>
>> Quoted from Linus[2]:
>>
>> "It's a horrible thing to use, in that it adds extra cruft to the
>> source code, and then shuts up a compiler warning (even the _reliable_
>> warnings from gcc)."
>>
>> The gcc option "-Wmaybe-uninitialized" has been disabled and this change
>> will not produce any warnnings even with "make W=1".
>>
>> [1] https://github.com/KSPP/linux/issues/81
>> [2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
>>
>> Cc: Kees Cook <keescook@...omium.org>
>> Cc: Chao Yu <yuchao0@...wei.com>
>> Signed-off-by: Jason Yan <yanaijie@...wei.com>
>> ---
> 
> I'm fine with the patch since "-Wmaybe-uninitialized" has been disabled and
> I've also asked Kees for it in private previously.
> 
> I still remembered that Kees sent out a treewide patch. Sorry about that
> I don't catch up it... But what is wrong with the original patchset?
> 

Yes, Kees has remind me of that and I will let him handle it. So you can 
ignore this patch.

Thanks,
Jason

> Thanks,
> Gao Xiang
> 
> 
> .
>