From patchwork Mon Dec 5 22:10:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 13065121 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70A88C4708C for ; Mon, 5 Dec 2022 22:12:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231639AbiLEWL7 (ORCPT ); Mon, 5 Dec 2022 17:11:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233686AbiLEWLz (ORCPT ); Mon, 5 Dec 2022 17:11:55 -0500 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0E761A216 for ; Mon, 5 Dec 2022 14:11:52 -0800 (PST) Received: from fsav411.sakura.ne.jp (fsav411.sakura.ne.jp [133.242.250.110]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 2B5MBo19027801; Tue, 6 Dec 2022 07:11:50 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav411.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav411.sakura.ne.jp); Tue, 06 Dec 2022 07:11:50 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav411.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 2B5MAZtx027513 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Tue, 6 Dec 2022 07:10:35 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: Date: Tue, 6 Dec 2022 07:10:31 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: [PATCH] fbdev: fbcon: release buffer when fbcon_do_set_font() failed Content-Language: en-US To: Daniel Vetter , Helge Deller , Shigeru Yoshida References: <000000000000e2efc305ef0d341f@google.com> Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org From: Tetsuo Handa In-Reply-To: <000000000000e2efc305ef0d341f@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org syzbot is reporting memory leak at fbcon_do_set_font() [1], for commit a5a923038d70 ("fbdev: fbcon: Properly revert changes when vc_resize() failed") missed that the buffer might be newly allocated by fbcon_set_font(). Link: https://syzkaller.appspot.com/bug?extid=25bdb7b1703639abd498 [1] Reported-by: syzbot Signed-off-by: Tetsuo Handa Tested-by: syzbot Fixes: a5a923038d70 ("fbdev: fbcon: Properly revert changes when vc_resize() failed") --- drivers/video/fbdev/core/fbcon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 098b62f7b701..8363f3b2b452 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2450,7 +2450,8 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount, if (userfont) { p->userfont = old_userfont; - REFCOUNT(data)--; + if (--REFCOUNT(data) == 0) + kfree(data - FONT_EXTRA_WORDS * sizeof(int)); } vc->vc_font.width = old_width;