Re: [MAINTAINERS/KERNEL SUMMIT] Trust and maintenance of file systems

[Segher Boessenkool <segher@kernel.crashing.org>]

On Thu, Sep 07, 2023 at 02:23:00PM +0300, Dan Carpenter wrote:
> On Thu, Sep 07, 2023 at 06:04:09AM -0500, Segher Boessenkool wrote:
> > On Thu, Sep 07, 2023 at 12:48:25PM +0300, Dan Carpenter via Gcc-patches wrote:
> > > I started to hunt
> > > down all the Makefile which add a -Werror but there are a lot and
> > > eventually I got bored and gave up.
> > 
> > I have a patch stack for that, since 2014 or so.  I build Linux with
> > unreleased GCC versions all the time, so pretty much any new warning is
> > fatal if you unwisely use -Werror.
> > 
> > > Someone should patch GCC so there it checks an environment variable to
> > > ignore -Werror.  Somethine like this?
> > 
> > No.  You should patch your program, instead.
> 
> There are 2930 Makefiles in the kernel source.

Yes.  And you need patches to about thirty.  Or a bit more, if you want
to do it more cleanly.  This isn't a guess.

> > One easy way is to add a
> > -Wno-error at the end of your command lines.  Or even just -w if you
> > want or need a bigger hammer.
> 
> I tried that.  Some of the Makefiles check an environemnt variable as
> well if you want to turn off -Werror.  It's not a complete solution at
> all.  I have no idea what a complete solution looks like because I gave
> up.

A solution can not involve changing the compiler.  That is just saying
the kernel doesn't know how to fix its own problems, so let's give the
compiler some more unnecessary problems.

> > Or nicer, put it all in Kconfig, like powerpc already has for example.
> > There is a CONFIG_WERROR as well, so maybe use that in all places?
> 
> That's a good idea but I'm trying to compile old kernels and not the
> current kernel.

You can patch older kernels, too, you know :-)

If you need to not make any changes to your source code for some crazy
reason (political perhaps?), just use a shell script or shell function
instead of invoking the compiler driver directly?


Segher

Segher