From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>
Subject: [PATCH bpf-next 01/12] libbpf: fix bpf_prog_load() log_buf logic for log_level 0
Date: Wed, 8 Dec 2021 16:30:22 -0800 [thread overview]
Message-ID: <20211209003033.3962657-2-andrii@kernel.org> (raw)
In-Reply-To: <20211209003033.3962657-1-andrii@kernel.org>
To unify libbpf APIs behavior w.r.t. log_buf and log_level, fix
bpf_prog_load() to follow the same logic as bpf_btf_load() and
high-level bpf_object__load() API will follow in the subsequent patches:
- if log_level is 0 and non-NULL log_buf is provided by a user, attempt
load operation initially with no log_buf and log_level set;
- if successful, we are done, return new FD;
- on error, retry the load operation with log_level bumped to 1 and
log_buf set; this way verbose logging will be requested only when we
are sure that there is a failure, but will be fast in the
common/expected success case.
Of course, user can still specify log_level > 0 from the very beginning
to force log collection.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/bpf.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 4e7836e1a7b5..c7627fc18952 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -303,10 +303,6 @@ int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type,
if (log_level && !log_buf)
return libbpf_err(-EINVAL);
- attr.log_level = log_level;
- attr.log_buf = ptr_to_u64(log_buf);
- attr.log_size = log_size;
-
func_info_rec_size = OPTS_GET(opts, func_info_rec_size, 0);
func_info = OPTS_GET(opts, func_info, NULL);
attr.func_info_rec_size = func_info_rec_size;
@@ -321,6 +317,12 @@ int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type,
attr.fd_array = ptr_to_u64(OPTS_GET(opts, fd_array, NULL));
+ if (log_level) {
+ attr.log_buf = ptr_to_u64(log_buf);
+ attr.log_size = log_size;
+ attr.log_level = log_level;
+ }
+
fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
if (fd >= 0)
return fd;
@@ -366,16 +368,17 @@ int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type,
goto done;
}
- if (log_level || !log_buf)
- goto done;
+ if (log_level == 0 && !log_buf) {
+ /* log_level == 0 with non-NULL log_buf requires retrying on error
+ * with log_level == 1 and log_buf/log_buf_size set, to get details of
+ * failure
+ */
+ attr.log_buf = ptr_to_u64(log_buf);
+ attr.log_size = log_size;
+ attr.log_level = 1;
- /* Try again with log */
- log_buf[0] = 0;
- attr.log_buf = ptr_to_u64(log_buf);
- attr.log_size = log_size;
- attr.log_level = 1;
-
- fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
+ fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
+ }
done:
/* free() doesn't affect errno, so we don't need to restore it */
free(finfo);
--
2.30.2
next prev parent reply other threads:[~2021-12-09 0:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 0:30 [PATCH bpf-next 00/12] Enhance and rework logging controls in libbpf Andrii Nakryiko
2021-12-09 0:30 ` Andrii Nakryiko [this message]
2021-12-09 0:30 ` [PATCH bpf-next 02/12] libbpf: add OPTS-based bpf_btf_load() API Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 03/12] libbpf: allow passing preallocated log_buf when loading BTF into kernel Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 04/12] libbpf: allow passing user log setting through bpf_object_open_opts Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 05/12] libbpf: improve logging around BPF program loading Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 06/12] libbpf: preserve kernel error code and remove kprobe prog type guessing Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 07/12] libbpf: add per-program log buffer setter and getter Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 08/12] libbpf: deprecate bpf_object__load_xattr() Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 09/12] selftests/bpf: replace all uses of bpf_load_btf() with bpf_btf_load() Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 10/12] selftests/bpf: add test for libbpf's custom log_buf behavior Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 11/12] selftests/bpf: remove the only use of deprecated bpf_object__load_xattr() Andrii Nakryiko
2021-12-09 0:30 ` [PATCH bpf-next 12/12] bpftool: switch bpf_object__load_xattr() to bpf_object__load() Andrii Nakryiko
2021-12-09 0:48 ` [PATCH bpf-next 00/12] Enhance and rework logging controls in libbpf Andrii Nakryiko
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