bpf: Fix bpf_prog_test_run_tracing for !CONFIG_NET

test_run.o is not built when CONFIG_NET is not set and
bpf_prog_test_run_tracing being referenced in bpf_trace.o causes the
linker error:

ld: kernel/trace/bpf_trace.o:(.rodata+0x38): undefined reference to
 `bpf_prog_test_run_tracing'

Add a __weak function in bpf_trace.c to handle this.

Fixes: da00d2f117a0 ("bpf: Add test ops for BPF_PROG_TYPE_TRACING")
Signed-off-by: KP Singh <kpsingh@google.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200305220127.29109-1-kpsingh@chromium.org

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 363e0a2..6a490d8 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1252,6 +1252,13 @@ static bool tracing_prog_is_valid_access(int off, int size,
        return btf_ctx_access(off, size, type, prog, info);
 }
 
+int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,
+                                    const union bpf_attr *kattr,
+                                    union bpf_attr __user *uattr)
+{
+       return -ENOTSUPP;
+}
+
 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
        .get_func_proto  = raw_tp_prog_func_proto,
        .is_valid_access = raw_tp_prog_is_valid_access,