4 files changed, 17 insertions, 4 deletions

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 9cd015574e83..a1db869a6fda 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -223,7 +223,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
 		return -EINVAL;
 
 	log_level = load_attr->log_level;
-	if (log_level > 2 || (log_level && !log_buf))
+	if (log_level > (4 | 2 | 1) || (log_level && !log_buf))
 		return -EINVAL;
 
 	name_len = load_attr->name ? strlen(load_attr->name) : 0;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 6ffdd79bea89..e2c0df7b831f 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -92,7 +92,7 @@ struct bpf_load_program_attr {
 #define MAPS_RELAX_COMPAT	0x01
 
 /* Recommend log buffer size */
-#define BPF_LOG_BUF_SIZE (256 * 1024)
+#define BPF_LOG_BUF_SIZE (16 * 1024 * 1024) /* verifier maximum in kernels <= 5.1 */
 LIBBPF_API int
 bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
 		       char *log_buf, size_t log_buf_sz);
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 11c25d9ea431..e1e4d35cf08e 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -152,6 +152,7 @@ struct bpf_program {
 		};
 	} *reloc_desc;
 	int nr_reloc;
+	int log_level;
 
 	struct {
 		int nr;
@@ -1494,6 +1495,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 {
 	struct bpf_load_program_attr load_attr;
 	char *cp, errmsg[STRERR_BUFSIZE];
+	int log_buf_size = BPF_LOG_BUF_SIZE;
 	char *log_buf;
 	int ret;
 
@@ -1514,21 +1516,30 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 	load_attr.line_info = prog->line_info;
 	load_attr.line_info_rec_size = prog->line_info_rec_size;
 	load_attr.line_info_cnt = prog->line_info_cnt;
+	load_attr.log_level = prog->log_level;
 	if (!load_attr.insns || !load_attr.insns_cnt)
 		return -EINVAL;
 
-	log_buf = malloc(BPF_LOG_BUF_SIZE);
+retry_load:
+	log_buf = malloc(log_buf_size);
 	if (!log_buf)
 		pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 
-	ret = bpf_load_program_xattr(&load_attr, log_buf, BPF_LOG_BUF_SIZE);
+	ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
 
 	if (ret >= 0) {
+		if (load_attr.log_level)
+			pr_debug("verifier log:\n%s", log_buf);
 		*pfd = ret;
 		ret = 0;
 		goto out;
 	}
 
+	if (errno == ENOSPC) {
+		log_buf_size <<= 1;
+		free(log_buf);
+		goto retry_load;
+	}
 	ret = -LIBBPF_ERRNO__LOAD;
 	cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
 	pr_warning("load bpf program failed: %s\n", cp);
@@ -2938,6 +2949,7 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
 		bpf_program__set_expected_attach_type(prog,
 						      expected_attach_type);
 
+		prog->log_level = attr->log_level;
 		if (!first_prog)
 			first_prog = prog;
 	}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c70785cc8ef5..531323391d07 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -314,6 +314,7 @@ struct bpf_prog_load_attr {
 	enum bpf_prog_type prog_type;
 	enum bpf_attach_type expected_attach_type;
 	int ifindex;
+	int log_level;
 };
 
 LIBBPF_API int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,