diff --git a/lib/libkldelf/ef.c b/lib/libkldelf/ef.c
--- a/lib/libkldelf/ef.c
+++ b/lib/libkldelf/ef.c
@@ -97,13 +97,13 @@
 {
 
 	if ((phdr->p_flags & PF_W) == 0) {
-		printf("text=0x%jx ", (uintmax_t)phdr->p_filesz);
+		warnx("text=0x%jx ", (uintmax_t)phdr->p_filesz);
 	} else {
-		printf("data=0x%jx", (uintmax_t)phdr->p_filesz);
+		warnx("data=0x%jx", (uintmax_t)phdr->p_filesz);
 		if (phdr->p_filesz < phdr->p_memsz)
-			printf("+0x%jx",
+			warnx("+0x%jx",
 			    (uintmax_t)(phdr->p_memsz - phdr->p_filesz));
-		printf(" ");
+		warnx(" ");
 	}
 }
 
@@ -612,7 +612,7 @@
 		}
 	}
 	if (verbose > 1)
-		printf("\n");
+		warnx("\n");
 	if (phdyn == NULL) {
 		warnx("Skipping %s: not dynamically-linked",
 		    ef->ef_name);
diff --git a/lib/libkldelf/ef_obj.c b/lib/libkldelf/ef_obj.c
--- a/lib/libkldelf/ef_obj.c
+++ b/lib/libkldelf/ef_obj.c
@@ -345,20 +345,20 @@
 	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 	    (ef->nrel != 0 && ef->reltab == NULL) ||
 	    (ef->nrela != 0 && ef->relatab == NULL)) {
-		printf("malloc failed\n");
+		warnx("malloc failed\n");
 		error = ENOMEM;
 		goto out;
 	}
 
 	if (elf_read_symbols(efile, symtabindex, &ef->ddbsymcnt,
 	    &ef->ddbsymtab) != 0) {
-		printf("elf_read_symbols failed\n");
+		warnx("elf_read_symbols failed\n");
 		goto out;
 	}
 
 	if (elf_read_string_table(efile, &shdr[symstrindex], &ef->ddbstrcnt,
 	    &ef->ddbstrtab) != 0) {
-		printf("elf_read_string_table failed\n");
+		warnx("elf_read_string_table failed\n");
 		goto out;
 	}
 
@@ -367,7 +367,7 @@
 	    shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 		if (elf_read_string_table(efile, &shdr[hdr->e_shstrndx],
 		    &ef->shstrcnt, &ef->shstrtab) != 0) {
-			printf("elf_read_string_table failed\n");
+			warnx("elf_read_string_table failed\n");
 			goto out;
 		}
 	}
@@ -413,7 +413,7 @@
 			ef->reltab[rl].sec = shdr[i].sh_info;
 			if (elf_read_rel(efile, i, &ef->reltab[rl].nrel,
 			    &ef->reltab[rl].rel) != 0) {
-				printf("elf_read_rel failed\n");
+				warnx("elf_read_rel failed\n");
 				goto out;
 			}
 			rl++;
@@ -422,7 +422,7 @@
 			ef->relatab[ra].sec = shdr[i].sh_info;
 			if (elf_read_rela(efile, i, &ef->relatab[ra].nrela,
 			    &ef->relatab[ra].rela) != 0) {
-				printf("elf_read_rela failed\n");
+				warnx("elf_read_rela failed\n");
 				goto out;
 			}
 			ra++;