e6340b6526
Since b8c96a6b466c ("certs: simplify $(srctree)/ handling and remove
config_filename macro"), when CONFIG_MODULE_SIG_KEY is empty,
signing_key.x509 fails to build:
CERT certs/signing_key.x509
Usage: extract-cert <source> <dest>
make[1]: *** [certs/Makefile:78: certs/signing_key.x509] Error 2
make: *** [Makefile:1831: certs] Error 2
Pass "" to the first argument of extract-cert to fix the build error.
Link: https://lore.kernel.org/linux-kbuild/20220120094606.2skuyb26yjlnu66q@lion.mk-sys.cz/T/#u
Fixes: b8c96a6b466c ("certs: simplify $(srctree)/ handling and remove config_filename macro")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Michal Kubecek <mkubecek@suse.cz>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.