Does vdso_install attempt to re-compile objects under root privilege?

From: Masahiro Yamada
Date: Wed Apr 03 2019 - 01:18:32 EST


Hi.

I have a question about 'vdso_install'.


In my understanding, vdso is embedded in the kernel.
In addition, you can run 'make vdso_install'
to install an unstripped version of vdso.
(Mainly, debugging purpose?)

By default, 'make vdso_install' will install it to
/lib/modules/$(uname -r)/vdso/.


Since that directly is owned by root,
'make vdso_install' could potentially be
executed by root, isn't it?


Currently, 'vdso_install' depends on vdso,
so it may cause recompilation of objects
in the source tree.


This violates the basic rule:
"Installation targets must not modify the source tree".

We often miss this point. For example, see
commit 19514fc665ffbce624785f76ee7ad0ea6378a527


If this is a problem, I will fix Makefiles to
make 'vdso_install' not depend on vdso

Thanks.


--
Best Regards
Masahiro Yamada