[PATCH bpf 2/2] bpf: selftest to verify mixing bpf2bpf calls and tailcalls with insn patch
From: John Fastabend <john.fastabend@gmail.com>
Date: 2021-06-08 19:40:05
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
This adds some extra noise to the tailcall_bpf2bpf4 tests that will cause verifier to patch insns. This then moves around subprog start/end insn index and poke descriptor insn index to ensure that verify and JIT will continue to track these correctly. Reviewed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- .../selftests/bpf/progs/tailcall_bpf2bpf4.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c b/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c
index 9a1b166b7fbe..0d70de5f97e2 100644
--- a/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c
+++ b/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c@@ -2,6 +2,13 @@ #include <linux/bpf.h> #include <bpf/bpf_helpers.h> +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u32)); +} nop_table SEC(".maps"); + struct { __uint(type, BPF_MAP_TYPE_PROG_ARRAY); __uint(max_entries, 3);
@@ -11,9 +18,19 @@ struct { static volatile int count; +__noinline +int subprog_noise(struct __sk_buff *skb) +{ + __u32 key = 0; + + bpf_map_lookup_elem(&nop_table, &key); + return 0; +} + __noinline int subprog_tail_2(struct __sk_buff *skb) { + subprog_noise(skb); bpf_tail_call_static(skb, &jmp_table, 2); return skb->len * 3; }