linux-kernel - Re: [PATCH] debugfs: Check return value of debugfs_real

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Message-ID: <20180328181456.GA87376@google.com>
Date:   Wed, 28 Mar 2018 11:14:56 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Manoj Gupta <manojgupta@...omium.org>,
        linux-kernel@...r.kernel.org, Josh Poimboeuf <jpoimboe@...hat.com>
Subject: Re: [PATCH] debugfs: Check return value of debugfs_real_fops() for
 NULL

El Wed, Mar 28, 2018 at 08:05:56PM +0200 Greg Kroah-Hartman ha dit:

> 
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
> 
> A: No.
> Q: Should I include quotations after my reply?
> 
> http://daringfireball.net/2007/07/on_top
> 
> On Wed, Mar 28, 2018 at 07:47:53AM -0700, Manoj Gupta wrote:
> > Please note that there is nothing wrong in the generated code, just
> > that it confuses objtool.
> 
> Then fix the tool, the C code is correct :)
> 
> > Clang has simply omitted the statement where NULL is returned since
> > the pointer was always dereferenced post inlining.
> 
> Then tell clang not to do that, like we tell gcc not to do that as that
> is a foolish thing for a compiler to do when building the kernel.

Thanks all for your input, we'll try to get
-fno-delete-null-pointer-checks or a similar flag to be added to
clang.