selftests/bpf: Fix failure path in send_signal test

[kernel-patches-daemon-bpf]

Pull request for series with
subject: selftests/bpf: Fix failure path in send_signal test
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813

[kernel-patches-daemon-bpf]

Upstream branch: 3249e8a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-review-bot]

commit dfcd8cbada1cce92f24923a824935527506334ea
Author: Alexei Starovoitov <[email protected]>

selftests/bpf: Fix failure path in send_signal test

This patch fixes a test hang where the parent process closes pipes before
the child process exits, causing the child to enter an infinite loop and
the parent to hang in wait(NULL). The fix adds kill(pid, SIGKILL) before
the goto statement when skel open/load fails.

> diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> index 1702aa592..61521dc76 100644
> --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c
> +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> @@ -110,8 +110,10 @@ static void test_send_signal_common(struct perf_event_attr *attr,
>  	close(pipe_p2c[0]); /* close read */
>
>  	skel = test_send_signal_kern__open_and_load();
> -	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
> +	if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) {
> +		kill(pid, SIGKILL);
>  		goto skel_open_load_failure;
> +	}

The fix addresses the skel_open_and_load failure path, but does this same
issue affect the other early failure paths in test_send_signal_common()?

Looking at the code after this hunk:

	if (!attr) {
		err = test_send_signal_kern__attach(skel);
		if (!ASSERT_OK(err, "skel_attach")) {
			err = -1;
			goto destroy_skel;
		}
	} else {
		[ ... ]
		if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) {
			err = -1;
			goto destroy_skel;
		}

		skel->links.send_signal_perf =
			bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd);
		if (!ASSERT_OK_PTR(skel->links.send_signal_perf, "attach_perf_event"))
			goto disable_pmu;
	}

	/* wait until child signal handler installed */
	ASSERT_EQ(read(pipe_c2p[0], buf, 1), 1, "pipe_read");

All three failure paths (attach, perf_event_open, attach_perf_event) occur
before reading from the child at pipe_c2p[0]. They goto labels that
eventually reach skel_open_load_failure without killing the child first.
Won't these paths trigger the same infinite loop bug described in the
commit message?

---

AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

In-Reply-To-Subject: selftests/bpf: Fix failure path in send_signal test
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/19323536860

[kernel-patches-daemon-bpf]

Forwarding comment 3526005172 via email
In-Reply-To: [email protected]
Patch: https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/

[kernel-patches-daemon-bpf]

Upstream branch: f1d8c65
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: f1d8c65
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: 93ce3be
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: 93ce3be
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: c1da3df
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: e5d2e34
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: fea3f5e
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

Upstream branch: 63066b7
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813
version: 1

[kernel-patches-daemon-bpf]

At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=1022813 expired. Closing PR.