[PATCH bpf-next v13 7/8] libbpf: Add syscall common attributes support for map_create
From: Leon Hwang <hidden>
Date: 2026-05-11 15:30:41
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
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 <redacted> --- tools/lib/bpf/bpf.c | 16 +++++++++++++++- tools/lib/bpf/bpf.h | 17 ++++++++++++++++- 2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 9d8740761b7a..483c02cf21d1 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c@@ -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); }
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 2c8e88ddb674..2312900a3263 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h@@ -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,
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2.54.0