lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 8 Apr 2020 22:49:48 +0200
From:   Arnd Bergmann <>
To:     Nicolas Pitre <>
Cc:     "" <>,
        Masahiro Yamada <>,
        Andrzej Hajda <>,
        Neil Armstrong <>,
        Laurent Pinchart <>,
        Jonas Karlman <>,
        Jernej Skrabec <>,
        David Airlie <>,
        Daniel Vetter <>,
        Kieran Bingham <>,
        "David S. Miller" <>,
        Saeed Mahameed <>,
        Leon Romanovsky <>,
        dri-devel <>,
        Linux-Renesas <>,
        Networking <>,
        linux-rdma <>
Subject: Re: [RFC 0/6] Regressions for "imply" behavior change

On Wed, Apr 8, 2020 at 10:38 PM Nicolas Pitre <> wrote:
> On Wed, 8 Apr 2020, Arnd Bergmann wrote:
> > I have created workarounds for the Kconfig files, which now stop using
> > imply and do something else in each case. I don't know whether there was
> > a bug in the kconfig changes that has led to allowing configurations that
> > were not meant to be legal even with the new semantics, or if the Kconfig
> > files have simply become incorrect now and the tool works as expected.
> In most cases it is the code that has to be fixed. It typically does:
>         if (IS_ENABLED(CONFIG_FOO))
>                 foo_init();
> Where it should rather do:
>                 foo_init();
> A couple of such patches have been produced and queued in their
> respective trees already.

I try to use IS_REACHABLE() only as a last resort, as it tends to
confuse users when a subsystem is built as a module and already
loaded but something relying on that subsystem does not use it.

In the six patches I made, I had to use IS_REACHABLE() once,
for the others I tended to use a Kconfig dependency like

'depends on FOO || FOO=n'

which avoids the case that IS_REACHABLE() works around badly.

I did come up with the IS_REACHABLE() macro originally, but that
doesn't mean I think it's a good idea to use it liberally ;-)


Powered by blists - more mailing lists