Re: [PATCH bpf-next 2/2] selftests/bpf: Add testcase for updating attached freplace prog to PROG_ARRAY map

[Yonghong Song <yonghong.song@linux.dev>]

On 7/24/24 5:32 PM, Leon Hwang wrote:
> Add a selftest to confirm the issue, which gets -EINVAL when update
> attached freplace prog to PROG_ARRAY map, has been fixed.
>
> cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
> 327/25  tailcalls/tailcall_freplace:OK
> 327     tailcalls:OK
> Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
>
> Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
> ---
>   .../selftests/bpf/prog_tests/tailcalls.c      | 76 ++++++++++++++++++-
>   .../selftests/bpf/progs/tailcall_freplace.c   | 33 ++++++++
>   .../testing/selftests/bpf/progs/tc_bpf2bpf.c  | 23 ++++++
>   3 files changed, 131 insertions(+), 1 deletion(-)
>   create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace.c
>   create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>
[...]
> diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> new file mode 100644
> index 0000000000000..80b5fa386ed9c
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> @@ -0,0 +1,33 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include "bpf_legacy.h"
> +
> +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 count = 0;
> +
> +__noinline
> +int subprog(struct __sk_buff *skb)
> +{
> +	count++;
> +
> +	bpf_tail_call_static(skb, &jmp_table, 0);
> +
> +	return count;
> +}
> +
> +SEC("freplace")
> +int entry(struct __sk_buff *skb)
> +{
> +	return subprog(skb);
> +}
> +
> +char __license[] SEC("license") = "GPL";
> +

extra line in the above.

> diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> new file mode 100644
> index 0000000000000..4810961554585
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include "bpf_legacy.h"
> +
> +__noinline
> +int subprog(struct __sk_buff *skb)
> +{
> +	volatile int ret = 1;
> +
> +	asm volatile (""::"r+"(ret));
> +	return ret;
> +}
> +
> +SEC("tc")
> +int entry(struct __sk_buff *skb)
> +{
> +	return subprog(skb);
> +}
> +
> +char __license[] SEC("license") = "GPL";
> +

extra line in the above.