[PATCH bpf-next] selftests/bpf: Drop the on_enter recursion check of task_local_storage

[PATCH bpf-next] selftests/bpf: Drop the on_enter recursion check of task_local_storage

[Qiliang Yuan]

test_recursion attaches on_enter to sys_enter and on_update to
bpf_local_storage_update, makes one syscall, and checks the task
storage values left behind and the recursion misses of both programs.

on_enter runs for every syscall of the system and returns early for
other tasks. On a preemptible kernel, a task can be preempted while it
runs on_enter, and a task entering a syscall on the same CPU then misses
the program. With other tests running in parallel, on_enter ends up
with recursion misses that have nothing to do with the test task, and
the check expecting none fails.

Drop the check. map_a holding 200, which only on_enter of the test task
writes, already shows that on_enter ran for it.

Fixes: 387b532138ee ("selftests/bpf: Tracing prog can still do lookup under busy lock")
Signed-off-by: Qiliang Yuan <odys.yuan@gmail.com>
---
 tools/testing/selftests/bpf/prog_tests/task_local_storage.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
index 5b2b56cc3a4f3..c03ea94325d9e 100644
--- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
+++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
@@ -138,12 +138,6 @@ static void test_recursion(void)
 	ASSERT_OK(err, "get prog info");
 	ASSERT_EQ(info.recursion_misses, 2, "on_update prog recursion");
 
-	prog_fd = bpf_program__fd(skel->progs.on_enter);
-	memset(&info, 0, sizeof(info));
-	err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
-	ASSERT_OK(err, "get prog info");
-	ASSERT_EQ(info.recursion_misses, 0, "on_enter prog recursion");
-
 out:
 	close(task_fd);
 	task_ls_recursion__destroy(skel);

---
base-commit: e1d84a37cba984388988d2f1ddc84561413f0db2
change-id: 20261009-selftests-bpf-task-ls-recursion-5a85b5d499ef

Best regards,
-- 
Qiliang Yuan <odys.yuan@gmail.com>