selftests/bpf: Add assert for user stacks in test_task_stack

commit 727a92d62f upstream.

This is a follow up to:
commit b8e3a87a62 ("bpf: Add crosstask check to __bpf_get_stack").

This test ensures that the task iterator only gets a single
user stack (for the current task).

Signed-off-by: Jordan Rome <linux@jordanrome.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20231112023010.144675-1-linux@jordanrome.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jordan Rome 2023-11-11 18:30:10 -08:00 committed by Greg Kroah-Hartman
parent cc9c60b253
commit 10193a5001
2 changed files with 7 additions and 0 deletions

View file

@ -150,6 +150,8 @@ static void test_task_stack(void)
do_dummy_read(skel->progs.dump_task_stack);
do_dummy_read(skel->progs.get_task_user_stacks);
ASSERT_EQ(skel->bss->num_user_stacks, 1, "num_user_stacks");
bpf_iter_task_stack__destroy(skel);
}

View file

@ -35,6 +35,8 @@ int dump_task_stack(struct bpf_iter__task *ctx)
return 0;
}
int num_user_stacks = 0;
SEC("iter/task")
int get_task_user_stacks(struct bpf_iter__task *ctx)
{
@ -51,6 +53,9 @@ int get_task_user_stacks(struct bpf_iter__task *ctx)
if (res <= 0)
return 0;
/* Only one task, the current one, should succeed */
++num_user_stacks;
buf_sz += res;
/* If the verifier doesn't refine bpf_get_task_stack res, and instead