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From:   Steve French <smfrench@gmail.com>
Date:   Tue, 1 Oct 2019 20:24:45 -0500
Message-ID: <CAH2r5mtzAgcJTrGuderq4DEHBXtPujcQ8DWJUzM0w=hHX8WbJQ@mail.gmail.com>
Subject: Re: Many unexpected warnings with current sparse
To:     Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Paulo Alcantara <paulo@paulo.ac>,
        David Howells <dhowells@redhat.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-sparse@vger.kernel.org,
        CIFS <linux-cifs@vger.kernel.org>
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On Tue, Oct 1, 2019 at 7:19 PM Luc Van Oostenryck
<luc.vanoostenryck@gmail.com> wrote:
>
> On Tue, Oct 01, 2019 at 06:14:23PM -0500, Steve French wrote:
> > It may be related to the following sparse make warning:
> >
> > No rule to make target
> > '/usr/include/x86_64-linux-gnu/bits/huge_val.h', needed by
> > 'sparse-llvm.o'
> >
> > I don't see huge_val.h in the Ubuntu 19 version of libc6-dev
>
> Yes, I've been bitten myself by this. It's fixed since a little while.
> So, just doing a clean build or removing all the deps (.*.d)
> should allow you to build sparse.
>
> I've verified the problem with asm and __inline in quota.h:
> it's autodetected by kconfig (CC_HAS_ASM_INLINE) so the exact config
> doesn't matter (only gcc's version does) but in all cases recent
> versions of sparse don't have a problem with it

Removed the dependencies and rebuilt as you suggested and it worked ...
and even better ... with the noise removed I now see two real bugs
(endian conversion missing on two lines) and only one possible problem
with sparse/gcc itself

Sparse now flags this line from one of Paulo's DFS features merged last year:

      struct smb_vol fake_vol = {0};

with

      "warning: Using plain integer as NULL pointer"

What is the recommended way to initialize a struct to avoid the sparse warning?


And what about the "namespace" warnings from the fscache (cache.o)
code that now show up?  I hadn't seen those before.
Any easy way to remove them?

"WARNING: module cifs uses symbol sigprocmask from namespace
fs/cifs/cache.o: $(deps_/home/sfrench/cifs-2.6/fs/cifs/cache.o), but
does not import it."
-- 
Thanks,

Steve