Re: [PATCH v5 7/9] selftests: livepatch: Add provides/obsoletes test scenarios

On Sun, Aug 9, 2026 at 5:31 PM <[email protected]> wrote:
>
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Race condition in test-provides-obsoletes.sh leading to flaky test failures.
> --
>
> --- Patch [7]: [PATCH v5 7/9] selftests: livepatch: Add provides/obsoletes test scenarios ---
> commit b45263c641deb4b2b48bbe22a1f0bf862b20a22f
> Author: Yafang Shao <[email protected]>
>
> selftests: livepatch: Add provides/obsoletes test scenarios
>
> This commit adds test scenarios for the new provides/obsoletes mechanism in
> livepatching. It introduces test-provides-obsoletes.sh to verify replacement,
> coexistence, and obsolete features.
>
> > diff --git a/tools/testing/selftests/livepatch/test-provides-obsoletes.sh b/tools/testing/selftests/livepatch/test-provides-obsoletes.sh
> > new file mode 100755
> > index 0000000000000..c740d463f556d
> > --- /dev/null
> > +++ b/tools/testing/selftests/livepatch/test-provides-obsoletes.sh
> [ ... ]
> > +start_test "provides 0 replaces provides 0"
> > +
> > +load_lp $MOD_LIVEPATCH provides=0
> > +load_lp $MOD_ATOMIC provides=0
> > +
> > +mods=($SYSFS_KLP_DIR/*)
> > +nmods=${#mods[@]}
> > +if [[ "$nmods" -ne 1 ]]; then
> > +     die "Expecting one module listed, found $nmods"
> > +fi
>
> [Severity: Medium]
> Could this directory check race with the asynchronous sysfs cleanup of the
> replaced patch?
>
> When load_lp returns, it polls until the new patch's sysfs transition file
> reads '0'. However, in the kernel, klp_try_complete_transition() clears
> klp_transition_patch before scheduling the asynchronous work to free replaced
> patches (klp_free_replaced_patches_async).
>
> If the test checks the directory count immediately, couldn't it sporadically
> see the old patch before the async cleanup completes, causing the test to
> flake with "Expecting one module listed, found 2"?
>
> This same pattern appears in the "same provides replaces" and "obsoletes
> replaces" test cases later in this script.

Makes sense.
I will update it in the next version.

-- 
Regards
Yafang