Commit 9489d457 authored by T.J. Mercier's avatar T.J. Mercier Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add test for truncated dmabuf_iter reads 



If many dmabufs are present, reads of the dmabuf iterator can be
truncated at PAGE_SIZE or user buffer size boundaries before the fix in
"bpf: Fix truncated dmabuf iterator reads". Add a test to
confirm truncation does not occur.

Signed-off-by: default avatarT.J. Mercier <tjmercier@google.com>
Link: https://lore.kernel.org/r/20251204000348.1413593-2-tjmercier@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 23448356

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

+42 −5
Original line number Diff line number Diff line
@@ -73,12 +73,10 @@ static int create_udmabuf(void) 
	return -1;

}



static int create_sys_heap_dmabuf(void)

static int create_sys_heap_dmabuf(size_t bytes)

{

	sysheap_test_buffer_size = 20 * getpagesize();



	struct dma_heap_allocation_data data = {

		.len = sysheap_test_buffer_size,

		.len = bytes,

		.fd = 0,

		.fd_flags = O_RDWR | O_CLOEXEC,

		.heap_flags = 0,
@@ -110,7 +108,9 @@ static int create_sys_heap_dmabuf(void) 
static int create_test_buffers(void)

{

	udmabuf = create_udmabuf();

	sysheap_dmabuf = create_sys_heap_dmabuf();



	sysheap_test_buffer_size = 20 * getpagesize();

	sysheap_dmabuf = create_sys_heap_dmabuf(sysheap_test_buffer_size);



	if (udmabuf < 0 || sysheap_dmabuf < 0)

		return -1;
@@ -219,6 +219,26 @@ static void subtest_dmabuf_iter_check_default_iter(struct dmabuf_iter *skel) 
	close(iter_fd);

}



static void subtest_dmabuf_iter_check_lots_of_buffers(struct dmabuf_iter *skel)

{

	int iter_fd;

	char buf[1024];

	size_t total_bytes_read = 0;

	ssize_t bytes_read;



	iter_fd = bpf_iter_create(bpf_link__fd(skel->links.dmabuf_collector));

	if (!ASSERT_OK_FD(iter_fd, "iter_create"))

		return;



	while ((bytes_read = read(iter_fd, buf, sizeof(buf))) > 0)

		total_bytes_read += bytes_read;



	ASSERT_GT(total_bytes_read, getpagesize(), "total_bytes_read");



	close(iter_fd);

}





static void subtest_dmabuf_iter_check_open_coded(struct dmabuf_iter *skel, int map_fd)

{

	LIBBPF_OPTS(bpf_test_run_opts, topts);
@@ -275,6 +295,23 @@ void test_dmabuf_iter(void) 
		subtest_dmabuf_iter_check_no_infinite_reads(skel);

	if (test__start_subtest("default_iter"))

		subtest_dmabuf_iter_check_default_iter(skel);

	if (test__start_subtest("lots_of_buffers")) {

		size_t NUM_BUFS = 100;

		int buffers[NUM_BUFS];

		int i;



		for (i = 0; i < NUM_BUFS; ++i) {

			buffers[i] = create_sys_heap_dmabuf(getpagesize());

			if (!ASSERT_OK_FD(buffers[i], "dmabuf_fd"))

				goto cleanup_bufs;

		}



		subtest_dmabuf_iter_check_lots_of_buffers(skel);



cleanup_bufs:

		for (--i; i >= 0; --i)

			close(buffers[i]);

	}

	if (test__start_subtest("open_coded"))

		subtest_dmabuf_iter_check_open_coded(skel, map_fd);