Re: [PATCH] x86/vdso, arm64/vdso: fix flip/flop vdso build bug

[Naohiro Aota]

On Fri, Jul 12, 2019 at 03:24:01PM +0900, Masahiro Yamada wrote:
> On Fri, Jul 12, 2019 at 2:46 PM Naohiro Aota <naohiro.aota@xxxxxxx> wrote:
> > Two consecutive "make" on an already compiled kernel tree will show
> > different behavior:
> >
> > $ make
> >   CALL    scripts/checksyscalls.sh
> >   CALL    scripts/atomic/check-atomics.sh
> >   DESCEND  objtool
> >   CHK     include/generated/compile.h
> >   VDSOCHK arch/x86/entry/vdso/vdso64.so.dbg
> >   VDSOCHK arch/x86/entry/vdso/vdso32.so.dbg
> > Kernel: arch/x86/boot/bzImage is ready  (#3)
> >   Building modules, stage 2.
> >   MODPOST 12 modules
> >
> > $ make
> >   CALL    scripts/checksyscalls.sh
> >   CALL    scripts/atomic/check-atomics.sh
> >   DESCEND  objtool
> >   CHK     include/generated/compile.h
> >   VDSO    arch/x86/entry/vdso/vdso64.so.dbg
> >   OBJCOPY arch/x86/entry/vdso/vdso64.so
> >   VDSO2C  arch/x86/entry/vdso/vdso-image-64.c
> >   CC      arch/x86/entry/vdso/vdso-image-64.o
> >   VDSO    arch/x86/entry/vdso/vdso32.so.dbg
> >   OBJCOPY arch/x86/entry/vdso/vdso32.so
> >   VDSO2C  arch/x86/entry/vdso/vdso-image-32.c
> >   CC      arch/x86/entry/vdso/vdso-image-32.o
> >   AR      arch/x86/entry/vdso/built-in.a
> >   AR      arch/x86/entry/built-in.a
> >   AR      arch/x86/built-in.a
> >   GEN     .version
> >   CHK     include/generated/compile.h
> >   UPD     include/generated/compile.h
> >   CC      init/version.o
> >   AR      init/built-in.a
> >   LD      vmlinux.o
> > <snip>
> >
> > This is causing "LD vmlinux" once every two times even without any
> > modifications. This is the same bug fixed in commit 92a4728608a8
> > ("x86/boot: Fix if_changed build flip/flop bug").  We cannot use two
> > "if_changed" in one target. Fix this build bug by merging two commands
> > into one function.
> >
> > Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
>
>
> The code looks OK, but you should split this
> into two patches, for arm64 and x86,
> and then add Fixes: for each of them.

Thanks, I'll split and add the tags.

> --
> Best Regards
> Masahiro Yamada