efi: fix NULL-deref in init error path

In cases where runtime services are not supported or have been disabled,
the runtime services workqueue will never have been allocated.

Do not try to destroy the workqueue unconditionally in the unlikely
event that EFI initialisation fails to avoid dereferencing a NULL
pointer.

Fixes: 98086df8b70c ("efi: add missed destroy_workqueue when efisubsys_init fails")
Cc: stable@vger.kernel.org
Cc: Li Heng <liheng40@huawei.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 09716ee..a2b0cbc 100644 (file)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -394,8 +394,8 @@ static int __init efisubsys_init(void)
        efi_kobj = kobject_create_and_add("efi", firmware_kobj);
        if (!efi_kobj) {
                pr_err("efi: Firmware registration failed.\n");
-               destroy_workqueue(efi_rts_wq);
-               return -ENOMEM;
+               error = -ENOMEM;
+               goto err_destroy_wq;
        }
 
        if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE |
@@ -443,7 +443,10 @@ err_unregister:
 err_put:
        kobject_put(efi_kobj);
        efi_kobj = NULL;
-       destroy_workqueue(efi_rts_wq);
+err_destroy_wq:
+       if (efi_rts_wq)
+               destroy_workqueue(efi_rts_wq);
+
        return error;
 }