selftests/bpf: Fix failure paths in send_signal test

When test_send_signal_kern__open_and_load() fails parent closes the
pipe which cases ASSERT_EQ(read(pipe_p2c...)) to fail, but child
continues and enters infinite loop, while parent is stuck in wait(NULL).
Other error paths have similar issue, so kill the child before waiting on it.

The bug was discovered while compiling all of selftests with -O1 instead of -O2
which caused progs/test_send_signal_kern.c to fail to load.

Fixes: ab8b7f0cb358 ("tools/bpf: Add self tests for bpf_send_signal_thread()")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251113171153.2583-1-alexei.starovoitov@gmail.com

diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
index 1702aa592c2c211479d26f2ebc1db85729dfef2e..7ac4d5a488aa5464e3d3c9cd3eb2bd2726c7ae57 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/send_signal.c
+++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
@@ -206,6 +206,11 @@ destroy_skel:
 skel_open_load_failure:
        close(pipe_c2p[0]);
        close(pipe_p2c[1]);
+       /*
+        * Child is either about to exit cleanly or stuck in case of errors.
+        * Nudge it to exit.
+        */
+       kill(pid, SIGKILL);
        wait(NULL);
 }