From: Feng zhou <zhoufeng.zf@bytedance.com>
To: netdev@vger.kernel.org, andrii.nakryiko@gmail.com
Cc: stephen@networkplumber.org, kuznet@ms2.inr.ac.ru,
duanxiongchun@bytedance.com, wangdongdong.6@bytedance.com,
chenzhuowen.simon@bytedance.com, zhoufeng.zf@bytedance.com,
cong.wang@bytedance.com
Subject: [PATCH iproute2] lib/bpf: Fix btf_load error lead to enable debug log
Date: Sun, 1 Aug 2021 14:07:09 +0800 [thread overview]
Message-ID: <20210801060709.4148-1-zhoufeng.zf@bytedance.com> (raw)
From: Feng Zhou <zhoufeng.zf@bytedance.com>
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>
---
lib/bpf_legacy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index 8a03b9c2..d824388c 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;
--
2.11.0
reply other threads:[~2021-08-01 6:07 UTC|newest]
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