diff --git a/tools/net/bpf_jit_disasm.c b/tools/net/bpf_jit_disasm.c
index 5b3241340945..544b05a53b70 100644
--- a/tools/net/bpf_jit_disasm.c
+++ b/tools/net/bpf_jit_disasm.c
@@ -98,6 +98,9 @@ static char *get_klog_buff(unsigned int *klen)
 	char *buff;
 
 	len = klogctl(CMD_ACTION_SIZE_BUFFER, NULL, 0);
+	if (len < 0)
+		return NULL;
+
 	buff = malloc(len);
 	if (!buff)
 		return NULL;