Commit 51fff408 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

selftests/bpf: Test a uptr struct spanning across pages. 



This patch tests the case when uptr has a struct spanning across two
pages. It is not supported now and EOPNOTSUPP is expected from the
syscall update_elem.

It also tests the whole uptr struct located exactly at the
end of a page and ensures that this case is accepted by update_elem.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20241023234759.860539-10-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4579b4a4

tools/testing/selftests/bpf/prog_tests/task_local_storage.c

+43 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <sys/syscall.h>   /* For SYS_xxx definitions */

#include <sys/types.h>

#include <sys/eventfd.h>

#include <sys/mman.h>

#include <test_progs.h>

#include "task_local_storage_helpers.h"

#include "task_local_storage.skel.h"
@@ -367,6 +368,46 @@ static void test_uptr_basic(void) 
	close(parent_task_fd);

}



static void test_uptr_across_pages(void)

{

	int page_size = getpagesize();

	struct value_type value = {};

	struct task_ls_uptr *skel;

	int err, task_fd, map_fd;

	void *mem;



	task_fd = sys_pidfd_open(getpid(), 0);

	if (!ASSERT_OK_FD(task_fd, "task_fd"))

		return;



	mem = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE,

		   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

	if (!ASSERT_OK_PTR(mem, "mmap(page_size * 2)")) {

		close(task_fd);

		return;

	}



	skel = task_ls_uptr__open_and_load();

	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))

		goto out;



	map_fd = bpf_map__fd(skel->maps.datamap);

	value.udata = mem + page_size - offsetof(struct user_data, b);

	err = bpf_map_update_elem(map_fd, &task_fd, &value, 0);

	if (!ASSERT_ERR(err, "update_elem(udata)"))

		goto out;

	ASSERT_EQ(errno, EOPNOTSUPP, "errno");



	value.udata = mem + page_size - sizeof(struct user_data);

	err = bpf_map_update_elem(map_fd, &task_fd, &value, 0);

	ASSERT_OK(err, "update_elem(udata)");



out:

	task_ls_uptr__destroy(skel);

	close(task_fd);

	munmap(mem, page_size * 2);

}



void test_task_local_storage(void)

{

	if (test__start_subtest("sys_enter_exit"))
@@ -379,4 +420,6 @@ void test_task_local_storage(void) 
		test_nodeadlock();

	if (test__start_subtest("uptr_basic"))

		test_uptr_basic();

	if (test__start_subtest("uptr_across_pages"))

		test_uptr_across_pages();

}