* [PATCH] lib/bpf: Fix btf_load error lead to enable debug log
@ 2021-07-29 4:55 Feng zhou
2021-07-30 18:40 ` Andrii Nakryiko
0 siblings, 1 reply; 3+ messages in thread
From: Feng zhou @ 2021-07-29 4:55 UTC (permalink / raw)
To: netdev
Cc: stephen, kuznet, duanxiongchun, wangdongdong.6,
chenzhuowen.simon, zhoufeng.zf
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] lib/bpf: Fix btf_load error lead to enable debug log
2021-07-29 4:55 [PATCH] lib/bpf: Fix btf_load error lead to enable debug log Feng zhou
@ 2021-07-30 18:40 ` Andrii Nakryiko
2021-08-01 5:59 ` [External] " zhoufeng
0 siblings, 1 reply; 3+ messages in thread
From: Andrii Nakryiko @ 2021-07-30 18:40 UTC (permalink / raw)
To: Feng zhou
Cc: Networking, Stephen Hemminger, kuznet, duanxiongchun,
Dongdong Wang, chenzhuowen.simon
On Wed, Jul 28, 2021 at 9:55 PM Feng zhou <zhoufeng.zf@bytedance.com> wrote:
>
> 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>
> ---
This seems to be targeted against iproute2? It would be good to
specify that as [PATCH iproute2] or something.
> 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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [External] Re: [PATCH] lib/bpf: Fix btf_load error lead to enable debug log
2021-07-30 18:40 ` Andrii Nakryiko
@ 2021-08-01 5:59 ` zhoufeng
0 siblings, 0 replies; 3+ messages in thread
From: zhoufeng @ 2021-08-01 5:59 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Networking, Stephen Hemminger, kuznet, duanxiongchun,
Dongdong Wang, chenzhuowen.simon, cong.wang
在 2021/7/31 上午2:40, Andrii Nakryiko 写道:
> On Wed, Jul 28, 2021 at 9:55 PM Feng zhou <zhoufeng.zf@bytedance.com> wrote:
>>
>> 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>
>> ---
>
> This seems to be targeted against iproute2? It would be good to
> specify that as [PATCH iproute2] or something.
>
>
Yeah, it's a good idea. I will resend it.
>> 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
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-08-01 5:59 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-29 4:55 [PATCH] lib/bpf: Fix btf_load error lead to enable debug log Feng zhou
2021-07-30 18:40 ` Andrii Nakryiko
2021-08-01 5:59 ` [External] " zhoufeng
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