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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 99B87C4708F for ; Wed, 2 Jun 2021 06:59:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 801E961359 for ; Wed, 2 Jun 2021 06:59:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231210AbhFBHAr (ORCPT ); Wed, 2 Jun 2021 03:00:47 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:60086 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229955AbhFBHAq (ORCPT ); Wed, 2 Jun 2021 03:00:46 -0400 Received: from relay2.suse.de (unknown [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 2E02B21935; Wed, 2 Jun 2021 06:59:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1622617143; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=vIrt8EnS10/pgZWAbdX1lqTwmvdy1dlnxZHsnjNKsOs=; b=ovoOoIHkju2CWKL9OqBZl15e4wjGMdCwum1lU4+NbV8EFI1O2WsF9aBVi6N2BYaCroRuz0 O7Uvo7dCYFIe3UAKnCD1jj+gXHSiIHimZiLJo7k03ZgXgII1aMrOe+4L/iy9cV+hfGyF/K oZfJ6vyb7YdkHDFE/bKn3YmHZYsDSnw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1622617143; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=vIrt8EnS10/pgZWAbdX1lqTwmvdy1dlnxZHsnjNKsOs=; b=ixB+6fxum+HeRIbC+nW0TnV4RY1bI+2M1J1tO4McMqyFdi0lU7JNw3JuCEnLKDOVNDbmXS IOBxdPGkASGLdzCw== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 17DEFA3B91; Wed, 2 Jun 2021 06:59:03 +0000 (UTC) Date: Wed, 02 Jun 2021 08:59:03 +0200 Message-ID: From: Takashi Iwai To: Dongliang Mu Cc: perex@perex.cz, tiwai@suse.com, dan.carpenter@oracle.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com Subject: Re: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register In-Reply-To: <20210602034136.2762497-1-mudongliangabcd@gmail.com> References: <20210602034136.2762497-1-mudongliangabcd@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 02 Jun 2021 05:41:36 +0200, Dongliang Mu wrote: > > The snd_ctl_led_sysfs_add and snd_ctl_led_sysfs_remove should contain > the refcount operations in pair. However, snd_ctl_led_sysfs_remove fails > to decrease the refcount to zero, which causes device_release never to > be invoked. This leads to memory leak to some resources, like struct > device_private. In addition, we also free some other similar memory > leaks in snd_ctl_led_init/snd_ctl_led_exit. > > Fix this by replacing device_del to device_unregister > in snd_ctl_led_sysfs_remove/snd_ctl_led_init/snd_ctl_led_exit. > > Note that, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device will > call kobject_release and delay the release of kobject, which will cause > use-after-free when the memory backing the kobject is freed at once. > > Reported-by: syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com > Fixes: a135dfb5de1 ("ALSA: led control - add sysfs kcontrol LED marking layer") > Signed-off-by: Dongliang Mu Applied now. Thanks. Takashi