From: Andrii Nakryiko <andrii@kernel.org>
Date: Thu, 9 Dec 2021 11:38:33 -0800
Subject: libbpf: Improve logging around BPF program loading
Patch-mainline: v5.17-rc1
Git-commit: ad9a7f96445b70c415d8e193f854321b110c890a
References: jsc#PED-1368
Add missing "prog '%s': " prefixes in few places and use consistently
markers for beginning and end of program load logs. Here's an example of
log output:
libbpf: prog 'handler': BPF program load failed: Permission denied
libbpf: -- BEGIN PROG LOAD LOG ---
arg#0 reference type('UNKNOWN ') size cannot be determined: -22
; out1 = in1;
0: (18) r1 = 0xffffc9000cdcc000
2: (61) r1 = *(u32 *)(r1 +0)
...
81: (63) *(u32 *)(r4 +0) = r5
R1_w=map_value(id=0,off=16,ks=4,vs=20,imm=0) R4=map_value(id=0,off=400,ks=4,vs=16,imm=0)
invalid access to map value, value_size=16 off=400 size=4
R4 min value is outside of the allowed memory range
processed 63 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
libbpf: failed to load program 'handler'
libbpf: failed to load object 'test_skeleton'
The entire verifier log, including BEGIN and END markers are now always
youtput during a single print callback call. This should make it much
easier to post-process or parse it, if necessary. It's not an explicit
API guarantee, but it can be reasonably expected to stay like that.
Also __bpf_object__open is renamed to bpf_object_open() as it's always
an adventure to find the exact function that implements bpf_object's
open phase, so drop the double underscored and use internal libbpf
naming convention.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-6-andrii@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/lib/bpf/libbpf.c | 38 ++++++++++----------
tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c | 6 ++-
2 files changed, 23 insertions(+), 21 deletions(-)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6662,8 +6662,10 @@ retry_load:
ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr);
if (ret >= 0) {
- if (log_buf && load_attr.log_level)
- pr_debug("verifier log:\n%s", log_buf);
+ if (log_buf && load_attr.log_level) {
+ pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n",
+ prog->name, log_buf);
+ }
if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) {
struct bpf_map *map;
@@ -6676,8 +6678,8 @@ retry_load:
if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
- pr_warn("prog '%s': failed to bind .rodata map: %s\n",
- prog->name, cp);
+ pr_warn("prog '%s': failed to bind map '%s': %s\n",
+ prog->name, map->real_name, cp);
/* Don't fail hard if can't bind rodata. */
}
}
@@ -6691,23 +6693,22 @@ retry_load:
if (!log_buf || errno == ENOSPC) {
log_buf_size = max((size_t)BPF_LOG_BUF_SIZE,
log_buf_size << 1);
-
free(log_buf);
goto retry_load;
}
ret = errno ? -errno : -LIBBPF_ERRNO__LOAD;
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
- pr_warn("load bpf program failed: %s\n", cp);
+ pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp);
pr_perm_msg(ret);
if (log_buf && log_buf[0] != '\0') {
ret = -LIBBPF_ERRNO__VERIFY;
- pr_warn("-- BEGIN DUMP LOG ---\n");
- pr_warn("\n%s\n", log_buf);
- pr_warn("-- END LOG --\n");
- } else if (insns_cnt >= BPF_MAXINSNS) {
- pr_warn("Program too large (%d insns), at most %d insns\n",
- insns_cnt, BPF_MAXINSNS);
+ pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n",
+ prog->name, log_buf);
+ }
+ if (insns_cnt >= BPF_MAXINSNS) {
+ pr_warn("prog '%s': program too large (%d insns), at most %d insns\n",
+ prog->name, insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (prog->type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
@@ -6931,9 +6932,8 @@ static int bpf_object_init_progs(struct
return 0;
}
-static struct bpf_object *
-__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
- const struct bpf_object_open_opts *opts)
+static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, size_t obj_buf_sz,
+ const struct bpf_object_open_opts *opts)
{
const char *obj_name, *kconfig, *btf_tmp_path;
struct bpf_object *obj;
@@ -7033,7 +7033,7 @@ __bpf_object__open_xattr(struct bpf_obje
return NULL;
pr_debug("loading %s\n", attr->file);
- return __bpf_object__open(attr->file, NULL, 0, &opts);
+ return bpf_object_open(attr->file, NULL, 0, &opts);
}
struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
@@ -7059,7 +7059,7 @@ bpf_object__open_file(const char *path,
pr_debug("loading %s\n", path);
- return libbpf_ptr(__bpf_object__open(path, NULL, 0, opts));
+ return libbpf_ptr(bpf_object_open(path, NULL, 0, opts));
}
struct bpf_object *
@@ -7069,7 +7069,7 @@ bpf_object__open_mem(const void *obj_buf
if (!obj_buf || obj_buf_sz == 0)
return libbpf_err_ptr(-EINVAL);
- return libbpf_ptr(__bpf_object__open(NULL, obj_buf, obj_buf_sz, opts));
+ return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, opts));
}
struct bpf_object *
@@ -7086,7 +7086,7 @@ bpf_object__open_buffer(const void *obj_
if (!obj_buf || obj_buf_sz == 0)
return errno = EINVAL, NULL;
- return libbpf_ptr(__bpf_object__open(NULL, obj_buf, obj_buf_sz, &opts));
+ return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, &opts));
}
int bpf_object__unload(struct bpf_object *obj)
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -217,14 +217,16 @@ static bool found;
static int libbpf_debug_print(enum libbpf_print_level level,
const char *format, va_list args)
{
- char *log_buf;
+ const char *log_buf;
if (level != LIBBPF_WARN ||
- strcmp(format, "libbpf: \n%s\n")) {
+ !strstr(format, "-- BEGIN PROG LOAD LOG --")) {
vprintf(format, args);
return 0;
}
+ /* skip prog_name */
+ va_arg(args, char *);
log_buf = va_arg(args, char *);
if (!log_buf)
goto out;