Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753105AbdHKM7K (ORCPT ); Fri, 11 Aug 2017 08:59:10 -0400 Received: from bran.ispras.ru ([83.149.199.196]:15736 "EHLO smtp.ispras.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752723AbdHKM7J (ORCPT ); Fri, 11 Aug 2017 08:59:09 -0400 From: Anton Vasilyev To: Bernie Thompson Cc: Anton Vasilyev , Bartlomiej Zolnierkiewicz , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: [PATCH] video: fbdev: udlfb: Fix use after free on dlfb_usb_probe error path Date: Fri, 11 Aug 2017 15:59:01 +0300 Message-Id: <1502456341-1783-1-git-send-email-vasilyev@ispras.ru> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 867 Lines: 27 If dlfb_usb_probe drops to error path then there is only one kref_init() call and no kref_get(), so second kref_put() leads to use after free. The patch removes superfluous kref_put on dlfb_usb_probe error path. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Anton Vasilyev --- drivers/video/fbdev/udlfb.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index 05ef657..f71b49f 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -1655,7 +1655,6 @@ static int dlfb_usb_probe(struct usb_interface *interface, error: if (dev) { - kref_put(&dev->kref, dlfb_free); /* ref for framebuffer */ kref_put(&dev->kref, dlfb_free); /* last ref from kref_init */ /* dev has been deallocated. Do not dereference */ -- 2.7.4