From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9ECC2C28CC5 for ; Sat, 8 Jun 2019 16:28:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61E1920840 for ; Sat, 8 Jun 2019 16:28:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QJrmg7BY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727264AbfFHQ2G (ORCPT ); Sat, 8 Jun 2019 12:28:06 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:45975 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727160AbfFHQ2G (ORCPT ); Sat, 8 Jun 2019 12:28:06 -0400 Received: by mail-wr1-f68.google.com with SMTP id f9so5049135wre.12 for ; Sat, 08 Jun 2019 09:28:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=WGZIJkWOD5HNBtJMxrjc9eWYDX3fZshEF6L9X8SRgBQ=; b=QJrmg7BYuSrMDmsaSjJaJ786HcQ1WBCcJtuTN6pDfVvAT12BXgznpY/gpKTatudvbr V7+66/Jt8/T4DRoOKCBhqrhSC5ful5WWnqYbwAprZCrU7Qbj/b0DwMoiirVvOlDVcHy7 1EBF4Q/Gi0bMzmMKp+s1REtTca+UgE5/9oX6X1sdAj6se8mRzCjdx2kfg5qAeKWNl74l PXOd5eI/Q3a3xvyL5Rrx2O7VoefPx/9MpyRx04fi4lDz61ibutot/vKkaHrvWEHsUE86 J6CnZY63UrxGm/rw9/nOfZrk+aAJ2I4tskosbWM8gD4eUNU8FvFdbkm1112eOcxbMi0+ zJQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=WGZIJkWOD5HNBtJMxrjc9eWYDX3fZshEF6L9X8SRgBQ=; b=n+66/6ONTHlSI6if15BZQBN56dkgrgn+SfKWbHnoftgmQyrhvwu7H5jQILZAOV5klO 1jmJ2gk58+mn++v8PdkbdD++RzZ2ktAoDbRXDUcHfA48id5x+ZO142EBW4NL2YvLlPaI UNb90LXRuutByOxqy4Unx/ZrFSo0kDudw3+AB4AXlm1gxJeFZuZY+NposSrvMgHOsW2N SCOFWZwpXXyn0RTIxf80SPJ9f7ai7ZYbAqURK6ZBlTaMhc2a39M5Tf6l/V8WpWrtzbrr nm2TDlG36AU1DT+KCYQLRBnsVPNjhVMDb+F7pPUDyv4yAcl6dEMrceJ3NKvzjUqrqu++ 3GcA== X-Gm-Message-State: APjAAAWx9QsdXS44Ur53vqvwwELhOvs8MmBzPxRmbw+slX5uAz+Z61dp wvmGTkZkTTnyFAgwoZtPuiQ= X-Google-Smtp-Source: APXvYqybB7/G0Ce4i90cr2B4jqQtyBOR/K1lJo1g+j06IFq+yPMqNvzHMtfi88o/oDvDLsNVwTh8DQ== X-Received: by 2002:adf:ec12:: with SMTP id x18mr6105952wrn.145.1560011284365; Sat, 08 Jun 2019 09:28:04 -0700 (PDT) Received: from zhanggen-UX430UQ ([108.61.173.19]) by smtp.gmail.com with ESMTPSA id k2sm5060032wrx.84.2019.06.08.09.28.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Jun 2019 09:28:03 -0700 (PDT) Date: Sun, 9 Jun 2019 00:27:54 +0800 From: Gen Zhang To: Greg KH Cc: jslaby@suse.com, nico@fluxnic.net, kilobyte@angband.pl, textshell@uchuujin.de, mpatocka@redhat.com, daniel.vetter@ffwll.ch, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] vt: Fix a missing-check bug in con_init() Message-ID: <20190608162754.GA2387@zhanggen-UX430UQ> References: <20190528004529.GA12388@zhanggen-UX430UQ> <20190608160138.GA3840@zhanggen-UX430UQ> <20190608162127.GA11699@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190608162127.GA11699@kroah.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 08, 2019 at 06:21:27PM +0200, Greg KH wrote: > On Sun, Jun 09, 2019 at 12:01:38AM +0800, Gen Zhang wrote: > > On Tue, May 28, 2019 at 08:45:29AM +0800, Gen Zhang wrote: > > > In function con_init(), the pointer variable vc_cons[currcons].d, vc and > > > vc->vc_screenbuf is allocated by kzalloc(). And they are used in the > > > following codes. However, kzalloc() returns NULL when fails, and null > > > pointer dereference may happen. And it will cause the kernel to crash. > > > Therefore, we should check the return value and handle the error. > > > > > > Further, since the allcoation is in a loop, we should free all the > > > allocated memory in a loop. > > > > > > Signed-off-by: Gen Zhang > > > Reviewed-by: Nicolas Pitre > > > --- > > > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > > > index fdd12f8..d50f68f 100644 > > > --- a/drivers/tty/vt/vt.c > > > +++ b/drivers/tty/vt/vt.c > > > @@ -3350,10 +3350,14 @@ static int __init con_init(void) > > > > > > for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) { > > > vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT); > > > + if (!vc) > > > + goto fail1; > > > INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK); > > > tty_port_init(&vc->port); > > > visual_init(vc, currcons, 1); > > > vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT); > > > + if (!vc->vc_screenbuf) > > > + goto fail2; > > > vc_init(vc, vc->vc_rows, vc->vc_cols, > > > currcons || !vc->vc_sw->con_save_screen); > > > } > > > @@ -3375,6 +3379,16 @@ static int __init con_init(void) > > > register_console(&vt_console_driver); > > > #endif > > > return 0; > > > +fail1: > > > + while (currcons > 0) { > > > + currcons--; > > > + kfree(vc_cons[currcons].d->vc_screenbuf); > > > +fail2: > > > + kfree(vc_cons[currcons].d); > > > + vc_cons[currcons].d = NULL; > > > + } > > > + console_unlock(); > > > + return -ENOMEM; > > > } > > > console_initcall(con_init); > > > > > > --- > > Can anyone look into this patch? It's already reviewed by Nicolas Pitre > > . > > It's in my queue. But note, given the previous history of your patches, > it's really low on my piority list at the moment :( > > greg k-h What? All the patches were revised iteratively according to the maintainers' or reviewers' advice. I don't think you should look down the patches from me. It seems not fair enough. :( Thanks Gen