From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luc Van Oostenryck Subject: Re: Many unexpected warnings with current sparse Date: Wed, 2 Oct 2019 03:35:38 +0200 Message-ID: <20191002013537.2bfopy3ke5kkmqep@desk.local> References: <20191001231017.67txq4dhrvhyzbu5@desk.local> <20191002001859.qeyo3btl7tosz3vo@desk.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Steve French Cc: Paulo Alcantara , David Howells , LKML , linux-sparse@vger.kernel.org, CIFS List-Id: linux-sparse@vger.kernel.org On Tue, Oct 01, 2019 at 08:24:45PM -0500, Steve French wrote: > On Tue, Oct 1, 2019 at 7:19 PM Luc Van Oostenryck > 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 Ahh, good! > (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? Well, personally, I simply use '{}'. GCC and sparse are happy with it but, IIRC, it's not allowed by the standard... > 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." This one is not from sparse, it's from modpost (see EXPORT_SYMBOL_NS). Cheers, -- Luc