linux-kernel - Re: [PATCH] checkpatch: avoid default n

lists.openwall.net		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 linux-cve-announce 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]

Message-ID: <c8d5cc6171d2cff131e8600ac57e2eb441812617.camel@perches.com>
Date:   Wed, 03 Jul 2019 08:37:55 -0700
From:   Joe Perches <joe@...ches.com>
To:     Yingjoe Chen <yingjoe.chen@...iatek.com>
Cc:     Miles Chen <miles.chen@...iatek.com>,
        Andy Whitcroft <apw@...onical.com>,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        wsd_upstream@...iatek.com
Subject: Re: [PATCH] checkpatch: avoid default n

On Wed, 2019-07-03 at 17:03 +0800, Yingjoe Chen wrote:
> On Wed, 2019-07-03 at 01:42 -0700, Joe Perches wrote:
> > On Wed, 2019-07-03 at 16:30 +0800, Miles Chen wrote:
> > > This change reports a warning when "default n" is used.
> > > 
> > > I have seen several "remove default n" patches, so I think
> > > it might be helpful to add this test in checkpatch.
> > > 
> > > tested:
> > > WARNING: 'default n' is the default value, no need to write it explicitly.
> > > +       default n
> > 
> > I don't think this is reasonable as there are
> > several uses like:
> > 
> > 		default y
> > 		default n if <foo>
> > 
> > For instance:
> > 
> > arch/alpha/Kconfig-config ALPHA_WTINT
> > arch/alpha/Kconfig-     bool "Use WTINT" if ALPHA_SRM || ALPHA_GENERIC
> > arch/alpha/Kconfig-     default y if ALPHA_QEMU
> > arch/alpha/Kconfig:     default n if ALPHA_EV5 || ALPHA_EV56 || (ALPHA_EV4 && !ALPHA_LCA)
> > arch/alpha/Kconfig:     default n if !ALPHA_SRM && !ALPHA_GENERIC
> 
> Hi,
> 
> 
> I've sent similar patch in 2016, my version won't complain about these.
> 
> https://lkml.org/lkml/2016/4/22/580

Hi again.

https://lore.kernel.org/lkml/1461259011.1918.23.camel@perches.com/

I would prefer a generic solution that also handles the
quoted use.

$ git grep -P 'default\s*\"[ynm]"' -- '*/Kconfig*'
arch/mips/Kconfig:      default "y"
arch/mips/Kconfig:      default "y"
arch/mips/Kconfig:      default "y"
arch/mips/Kconfig:      default "y"
arch/mips/cavium-octeon/Kconfig:        default "n"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/mips/cavium-octeon/Kconfig:        default "y"
arch/powerpc/Kconfig:   default "y" if PPC_POWERNV
arch/powerpc/Kconfig:   default "y" if PPC_POWERNV
arch/powerpc/Kconfig:   default "n"
drivers/auxdisplay/Kconfig:     default "n"
drivers/crypto/Kconfig: default "m"
drivers/rapidio/devices/Kconfig:        default "n"

or maybe 2 separate patches.

And the "default y" case and probably the
"default \!?EXPERT" is or should be generally
discouraged.  Especially for drivers.

https://lore.kernel.org/lkml/CAHk-=wiZ24JuVehJ5sEC0UG1Gk2nvB363wO02RRsR1oEht6R9Q@mail.gmail.com/