From: Andrea Righi <arighi@nvidia.com> mainline inclusion from mainline-v6.16-rc7 commit 7980ad7e4ca80f6c255f4473fba82a475342035a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IDC9YK Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- On single-CPU systems, ops.select_cpu() is never called, causing the EXIT_SELECT_CPU test case to wait indefinitely. Avoid the stall by skipping this specific sub-test when only one CPU is available. Reported-by: Phil Auld <pauld@redhat.com> Fixes: a5db7817af780 ("sched_ext: Add selftests") Signed-off-by: Andrea Righi <arighi@nvidia.com> Reviewed-by: Phil Auld <pauld@redhat.com> Tested-by: Phil Auld <pauld@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> --- tools/testing/selftests/sched_ext/exit.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/testing/selftests/sched_ext/exit.c b/tools/testing/selftests/sched_ext/exit.c index 9451782689de..ee25824b1cbe 100644 --- a/tools/testing/selftests/sched_ext/exit.c +++ b/tools/testing/selftests/sched_ext/exit.c @@ -22,6 +22,14 @@ static enum scx_test_status run(void *ctx) struct bpf_link *link; char buf[16]; + /* + * On single-CPU systems, ops.select_cpu() is never + * invoked, so skip this test to avoid getting stuck + * indefinitely. + */ + if (tc == EXIT_SELECT_CPU && libbpf_num_possible_cpus() == 1) + continue; + skel = exit__open(); SCX_ENUM_INIT(skel); skel->rodata->exit_point = tc; -- 2.34.1