[PATCH 5.15.y] Revert "selftests/bpf: Test tail call counting with bpf2bpf and data on stack"

[PATCH 5.15.y] Revert "selftests/bpf: Test tail call counting with bpf2bpf and data on stack"

[Samasth Norway Ananda]

This reverts commit 3eefb2fbf4ec1c1ff239b8b65e6e78aae335e4a6.

libbpf support for "tc" progs doesn't exist for the linux-5.15.y tree.
This commit was backported too far back in upstream, to a kernel where
the libbpf support was not there for the test.

Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>

Conflicts:
        tools/testing/selftests/bpf/prog_tests/tailcalls.c
        conflict was caused due to code overlap with the commit
        b06bde1c5ed6 ("selftests/bpf: Correct map_fd to data_fd in tailcalls")
        in the function test_tailcall_bpf2bpf_6(). As this function is
        removed by the revert conflict is resolved.
---
This was identified when we ran bpf selftest.
$ cd tools/testing/selftests/bpf
$ make test_progs
$ ./test_progs --name=ksyms_module
#137/1 tailcalls/tailcall_1:OK
#137/2 tailcalls/tailcall_2:OK
#137/3 tailcalls/tailcall_3:OK
#137/4 tailcalls/tailcall_4:OK
#137/5 tailcalls/tailcall_5:OK
#137/6 tailcalls/tailcall_bpf2bpf_1:OK
#137/7 tailcalls/tailcall_bpf2bpf_2:OK
#137/8 tailcalls/tailcall_bpf2bpf_3:OK
#137/9 tailcalls/tailcall_bpf2bpf_4:OK
#137/10 tailcalls/tailcall_bpf2bpf_5:OK
libbpf: prog 'classifier_0': missing BPF prog type, check ELF section name 'tc'
libbpf: failed to load program 'classifier_0'
libbpf: failed to load object 'tailcall_bpf2bpf6'
libbpf: failed to load BPF skeleton 'tailcall_bpf2bpf6': -22
test_tailcall_bpf2bpf_6:FAIL:open and load unexpected error: -22
#137/11 tailcalls/tailcall_bpf2bpf_6:FAIL
#137 tailcalls:FAIL
Summary: 0/10 PASSED, 0 SKIPPED, 2 FAILED
---
 .../selftests/bpf/prog_tests/tailcalls.c      | 55 -------------------
 .../selftests/bpf/progs/tailcall_bpf2bpf6.c   | 42 --------------
 2 files changed, 97 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c

diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
index 28e30ad4a30e..2e3e525e8579 100644
--- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -810,59 +810,6 @@ static void test_tailcall_bpf2bpf_4(bool noise)
 	bpf_object__close(obj);
 }
 
-#include "tailcall_bpf2bpf6.skel.h"
-
-/* Tail call counting works even when there is data on stack which is
- * not aligned to 8 bytes.
- */
-static void test_tailcall_bpf2bpf_6(void)
-{
-	struct tailcall_bpf2bpf6 *obj;
-	int err, map_fd, prog_fd, main_fd, data_fd, i, val;
-	LIBBPF_OPTS(bpf_test_run_opts, topts,
-		.data_in = &pkt_v4,
-		.data_size_in = sizeof(pkt_v4),
-		.repeat = 1,
-	);
-
-	obj = tailcall_bpf2bpf6__open_and_load();
-	if (!ASSERT_OK_PTR(obj, "open and load"))
-		return;
-
-	main_fd = bpf_program__fd(obj->progs.entry);
-	if (!ASSERT_GE(main_fd, 0, "entry prog fd"))
-		goto out;
-
-	map_fd = bpf_map__fd(obj->maps.jmp_table);
-	if (!ASSERT_GE(map_fd, 0, "jmp_table map fd"))
-		goto out;
-
-	prog_fd = bpf_program__fd(obj->progs.classifier_0);
-	if (!ASSERT_GE(prog_fd, 0, "classifier_0 prog fd"))
-		goto out;
-
-	i = 0;
-	err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
-	if (!ASSERT_OK(err, "jmp_table map update"))
-		goto out;
-
-	err = bpf_prog_test_run_opts(main_fd, &topts);
-	ASSERT_OK(err, "entry prog test run");
-	ASSERT_EQ(topts.retval, 0, "tailcall retval");
-
-	data_fd = bpf_map__fd(obj->maps.bss);
-	if (!ASSERT_GE(data_fd, 0, "bss map fd"))
-		goto out;
-
-	i = 0;
-	err = bpf_map_lookup_elem(data_fd, &i, &val);
-	ASSERT_OK(err, "bss map lookup");
-	ASSERT_EQ(val, 1, "done flag is set");
-
-out:
-	tailcall_bpf2bpf6__destroy(obj);
-}
-
 void test_tailcalls(void)
 {
 	if (test__start_subtest("tailcall_1"))
@@ -885,6 +832,4 @@ void test_tailcalls(void)
 		test_tailcall_bpf2bpf_4(false);
 	if (test__start_subtest("tailcall_bpf2bpf_5"))
 		test_tailcall_bpf2bpf_4(true);
-	if (test__start_subtest("tailcall_bpf2bpf_6"))
-		test_tailcall_bpf2bpf_6();
 }
diff --git a/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c b/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c
deleted file mode 100644
index 41ce83da78e8..000000000000
--- a/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c
+++ /dev/null
@@ -1,42 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/bpf.h>
-#include <bpf/bpf_helpers.h>
-
-#define __unused __attribute__((unused))
-
-struct {
-	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
-	__uint(max_entries, 1);
-	__uint(key_size, sizeof(__u32));
-	__uint(value_size, sizeof(__u32));
-} jmp_table SEC(".maps");
-
-int done = 0;
-
-SEC("tc")
-int classifier_0(struct __sk_buff *skb __unused)
-{
-	done = 1;
-	return 0;
-}
-
-static __noinline
-int subprog_tail(struct __sk_buff *skb)
-{
-	/* Don't propagate the constant to the caller */
-	volatile int ret = 1;
-
-	bpf_tail_call_static(skb, &jmp_table, 0);
-	return ret;
-}
-
-SEC("tc")
-int entry(struct __sk_buff *skb)
-{
-	/* Have data on stack which size is not a multiple of 8 */
-	volatile char arr[1] = {};
-
-	return subprog_tail(skb);
-}
-
-char __license[] SEC("license") = "GPL";
-- 
2.42.0

Re: [PATCH 5.15.y] Revert "selftests/bpf: Test tail call counting with bpf2bpf and data on stack"

[Greg KH]

On Fri, Feb 02, 2024 at 05:12:28PM -0800, Samasth Norway Ananda wrote:
> This reverts commit 3eefb2fbf4ec1c1ff239b8b65e6e78aae335e4a6.
> 
> libbpf support for "tc" progs doesn't exist for the linux-5.15.y tree.
> This commit was backported too far back in upstream, to a kernel where
> the libbpf support was not there for the test.
> 
> Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
> 
> Conflicts:
>         tools/testing/selftests/bpf/prog_tests/tailcalls.c
>         conflict was caused due to code overlap with the commit
>         b06bde1c5ed6 ("selftests/bpf: Correct map_fd to data_fd in tailcalls")
>         in the function test_tailcall_bpf2bpf_6(). As this function is
>         removed by the revert conflict is resolved.

Now qeued up, thanks.

greg k-h