[CRIU] [PATCHv7 01/33] ns: Introduce Time Namespace

[Thomas Gleixner]

On Wed, 16 Oct 2019, Vincenzo Frascino wrote:

< Trim 250+ lines ( 3+ pages) of pointlessly wasted electrons >

> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -1096,6 +1096,13 @@ config UTS_NS
> >  	  In this namespace tasks see different info provided with the
> >  	  uname() system call
> >  
> > +config TIME_NS
> > +	bool "TIME namespace"
> > +	default y
> 
> Having CONFIG_TIME_NS "default y" makes so that the option is selected even on
> the architectures that have no support for time namespaces.
> The direct consequence is that the fallbacks defined in this patch are never
> selected and this ends up in kernel compilation errors due to missing symbols.
> 
> The error below shows what happens on arm64 (similar behavior on other
> architectures):
> 
> aarch64-linux-gnu-ld: kernel/time/namespace.o: in function `timens_on_fork':
> kernel/time/namespace.c:321: undefined reference to `vdso_join_timens'
> 
> My proposal is to keep TIME_NS "default n" (just remove "default y"), let the
> architectures that enable time namespaces select it and make CONFIG_TIME_NS
> select GENERIC_VDSO_TIME_NS if arch has HAVE_GENERIC_VDSO.

Nah.

config TIME_NS
	bool "TIME namespace"
	depends on GENERIC_VDSO_TIME_NS
	default y

and in lib/vdso/Kconfig

config GENERIC_VDSO_TIME_NS
	bool

and let architectures which have support for the VDSO bits select it.

< Trim another gazillion of useless lines >

See: https://people.kernel.org/tglx/notes-about-netiquette

Thanks,

	tglx