[PATCH] lib/bpf: Fix btf_load error lead to enable debug log

From: Feng Zhou <redacted>

Use tc with no verbose, when bpf_btf_attach fail,
the conditions:
"if (fd < 0 && (errno == ENOSPC || !ctx->log_size))"
will make ctx->log_size != 0. And then, bpf_prog_attach,
ctx->log_size != 0. so enable debug log.
The verifier log sometimes is so chatty on larger programs.
bpf_prog_attach is failed.
"Log buffer too small to dump verifier log 16777215 bytes (9 tries)!"

BTF load failure does not affect prog load. prog still work.
So when BTF/PROG load fail, enlarge log_size and re-fail with
having verbose.

Signed-off-by: Feng Zhou <redacted>
---
  lib/bpf_legacy.c | 8 ++++----
  1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index 8a03b9c2..80c49f08 100644
--- a/lib/bpf_legacy.c
+++ b/lib/bpf_legacy.c

@@ -1525,13 +1525,13 @@ retry:
  	fd = bpf_prog_load_dev(prog->type, prog->insns, prog->size,
  			       prog->license, ctx->ifindex,
  			       ctx->log, ctx->log_size);
-	if (fd < 0 || ctx->verbose) {
+	if (fd < 0 && ctx->verbose) {
  		/* The verifier log is pretty chatty, sometimes so chatty
  		 * on larger programs, that we could fail to dump everything
  		 * into our buffer. Still, try to give a debuggable error
  		 * log for the user, so enlarge it and re-fail.
  		 */
-		if (fd < 0 && (errno == ENOSPC || !ctx->log_size)) {
+		if (errno == ENOSPC) {
  			if (tries++ < 10 && !bpf_log_realloc(ctx))
  				goto retry;
  

@@ -2068,8 +2068,8 @@ retry:
  	errno = 0;
  	fd = bpf_btf_load(ctx->btf_data->d_buf, ctx->btf_data->d_size,
  			  ctx->log, ctx->log_size);
-	if (fd < 0 || ctx->verbose) {
-		if (fd < 0 && (errno == ENOSPC || !ctx->log_size)) {
+	if (fd < 0 && ctx->verbose) {
+		if (errno == ENOSPC) {
  			if (tries++ < 10 && !bpf_log_realloc(ctx))
  				goto retry;