libbpf: Add syscall common attributes support for map_create

With the previous commit adding common attribute support for
BPF_MAP_CREATE, users can now retrieve detailed error messages when map
creation fails via the log_buf field.

Introduce struct bpf_log_opts with the following fields:
log_buf, log_size, log_level, and log_true_size.

Extend bpf_map_create_opts with a new field log_opts, allowing users to
capture and inspect log messages on map creation failures.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260512153157.28382-8-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Leon Hwang
2026-05-12 23:31:56 +08:00
committed by Alexei Starovoitov
parent 49f9b2b2a1
commit 702259006f
2 changed files with 31 additions and 2 deletions

View File

@@ -209,6 +209,9 @@ int bpf_map_create(enum bpf_map_type map_type,
const struct bpf_map_create_opts *opts)
{
const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size);
const size_t attr_common_sz = sizeof(struct bpf_common_attr);
struct bpf_common_attr attr_common;
struct bpf_log_opts *log_opts;
union bpf_attr attr;
int fd;
@@ -242,7 +245,18 @@ int bpf_map_create(enum bpf_map_type map_type,
attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL));
attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
log_opts = OPTS_GET(opts, log_opts, NULL);
if (log_opts && feat_supported(NULL, FEAT_BPF_SYSCALL_COMMON_ATTRS)) {
memset(&attr_common, 0, attr_common_sz);
attr_common.log_buf = ptr_to_u64(OPTS_GET(log_opts, buf, NULL));
attr_common.log_size = OPTS_GET(log_opts, size, 0);
attr_common.log_level = OPTS_GET(log_opts, level, 0);
fd = sys_bpf_ext_fd(BPF_MAP_CREATE, &attr, attr_sz, &attr_common, attr_common_sz);
OPTS_SET(log_opts, true_size, attr_common.log_true_size);
} else {
fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
OPTS_SET(log_opts, true_size, 0);
}
return libbpf_err_errno(fd);
}

View File

@@ -37,6 +37,18 @@ extern "C" {
LIBBPF_API int libbpf_set_memlock_rlim(size_t memlock_bytes);
struct bpf_log_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
char *buf;
__u32 size;
__u32 level;
__u32 true_size; /* out parameter set by kernel */
size_t :0;
};
#define bpf_log_opts__last_field true_size
struct bpf_map_create_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
@@ -57,9 +69,12 @@ struct bpf_map_create_opts {
const void *excl_prog_hash;
__u32 excl_prog_hash_size;
struct bpf_log_opts *log_opts;
size_t :0;
};
#define bpf_map_create_opts__last_field excl_prog_hash_size
#define bpf_map_create_opts__last_field log_opts
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
const char *map_name,