[Devel] [PATCH hci-8.1 v2 0/6] configs: a User Mode Linux kernel for the KUnit tests

[Konstantin Khorenko]

Eva Kurchatova wrote:
> Tested on 0a88195dfe7a (branch-rh10-6.12.0-211.52.1.22.x.vz10-ovz): the
> um config resolves with KASAN and SLUB_RCU_DEBUG on, the KASAN test and
> the module-only subsystems off, and no KUnit test left a module.
>
> Built with ARCH=um and booted with kasan_multi_shot: 183 pass, 0 fail.
> When I take CONFIG_KASAN out of the resolved config, or try to turn
> KUnit tests into modules, check_um_config.sh fails, naming the option.
> The Kconfig scan finds the same 110 tests I counted via grep.

Thank you for testing it and for the review.

> build_configs.sh turns WERROR on in every config when ENABLE_WERROR is
> set, the default of the dist-* targets in Makefile.variables, so a "make
> dist-rhel-configs" writes CONFIG_WERROR=y into the um config too, and
> the check then fails the build ("CONFIG_WERROR=y: set, the um layer has
> it off"). The published x86_64 configs have WERROR off, so I can't
> imagine this will affect CI; if it does run with it though,
> build_configs.sh should leave the um variant out.

Thanks for spotting it. We do not go through the dist-* targets:
git-publish.sh runs build_configs.sh directly,

  RHJOBS="$(nproc)" ARCH_MACH=x86_64 ./build_configs.sh kernel rhel
  RHJOBS="$(nproc)" ARCH_MACH=um ./build_configs.sh kernel rhel

so ENABLE_WERROR is never set there, and the um config keeps WERROR off.

The UML kernel does not build with -Werror for now anyway. lib/iomap.c
gets -Wmissing-prototypes for ioread64_lo_hi() and its siblings, as UML
includes asm-generic/iomap.h before readq is defined. Upstream fixed it
in dc90c890363d3 ("asm-generic/io.h: rework split ioread64/iowrite64
helpers", v6.15), but the rework touches the generic I/O headers of
every architecture, too intrusive to bring in for the sake of a test
kernel.

What your note did show is that our x86_64 kernels are built without
-Werror at all, unlike RHEL's: with no ENABLE_WERROR in git-publish.sh,
CONFIG_WERROR and CONFIG_KVM_WERROR stay off. That is not good, and we
will fix it with override files in custom-overrides/generic, which the
um layer still overrides with WERROR off:

https://virtuozzo.atlassian.net/browse/VSTOR-151903

> Updated https://bitbucket.org/virtuozzocore/hci-tests.vhistrg/pull-requests/9241 with follow-ups: Pass kasan_multi_shot, handle printk timestamp, removed KASAN report filter.

Thanks!

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team