From: Feng Zhou <zhoufeng.zf@bytedance.com>
Date: Sun, 1 Aug 2021 06:07:09 +0000 (+0800)
Subject: lib/bpf: Fix btf_load error lead to enable debug log
X-Git-Tag: v5.14.0~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be99929d60436d131aad1cf09b9216971846e32e;p=thirdparty%2Fiproute2.git

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

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 <zhoufeng.zf@bytedance.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---

diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index d57d26359..e8a41e6fb 100644
--- a/lib/bpf_legacy.c
+++ b/lib/bpf_legacy.c
@@ -1531,7 +1531,7 @@ retry:
 		 * 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 (fd < 0 && errno == ENOSPC) {
 			if (tries++ < 10 && !bpf_log_realloc(ctx))
 				goto retry;
 
@@ -2069,7 +2069,7 @@ retry:
 	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 && errno == ENOSPC) {
 			if (tries++ < 10 && !bpf_log_realloc(ctx))
 				goto retry;