diff --git a/tools/testing/selftests/wireguard/qemu/kernel.config b/tools/testing/selftests/wireguard/qemu/kernel.config
index cf05dde609a2..459b3a475c80 100644
--- a/tools/testing/selftests/wireguard/qemu/kernel.config
+++ b/tools/testing/selftests/wireguard/qemu/kernel.config
@@ -65,6 +65,7 @@ CONFIG_PROC_SYSCTL=y
 CONFIG_SYSFS=y
 CONFIG_TMPFS=y
 CONFIG_CONSOLE_LOGLEVEL_DEFAULT=15
+CONFIG_LOG_BUF_SHIFT=18
 CONFIG_PRINTK_TIME=y
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_LEGACY_VSYSCALL_NONE=y