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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 7AAECC43603 for ; Tue, 10 Dec 2019 22:08:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AE9920637 for ; Tue, 10 Dec 2019 22:08:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576015737; bh=+FSfsTMhWnVbXHveRqF4bTYhm7dm42KvOsciyFqV9ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gmTjj/h3HUNjWm9KLHCZmMN7FToepacO4k+DyC/DIGMWkntGjjLKiwldKeCo2sTLy UG4GLUSzldPmaozjRHT2MLxEqncKw532IpzOs/SMpRtmE3nnGtSfbegEdmeDO4F1o+ psi1gqV7B/AAp0xeW6cdEJWQB3+LfAVg2gbYtUaI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729282AbfLJWI4 (ORCPT ); Tue, 10 Dec 2019 17:08:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:35554 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728986AbfLJWEg (ORCPT ); Tue, 10 Dec 2019 17:04:36 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E9A02073B; Tue, 10 Dec 2019 22:04:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576015475; bh=+FSfsTMhWnVbXHveRqF4bTYhm7dm42KvOsciyFqV9ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WWsrAqW49fmgtunHsknrKAREpJfI41OBjmr617EMUq9jzjX9SPXmT0GO2HoICiq4k WyGqmbXXEBFfrfkTvBvZ/yCxPbU2v4qluBFLbAprkQYb93Sf27TQ+DWTN8GHQMTrmW Q+qzzH1ro74HnQnAeiyx0Si8C7HotQJeF+vvo+WY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , Sasha Levin , alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 4.14 080/130] ALSA: timer: Limit max amount of slave instances Date: Tue, 10 Dec 2019 17:02:11 -0500 Message-Id: <20191210220301.13262-80-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210220301.13262-1-sashal@kernel.org> References: <20191210220301.13262-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai [ Upstream commit fdea53fe5de532969a332d6e5e727f2ad8bf084d ] The fuzzer tries to open the timer instances as much as possible, and this may cause a system hiccup easily. We've already introduced the cap for the max number of available instances for the h/w timers, and we should put such a limit also to the slave timers, too. This patch introduces the limit to the multiple opened slave timers. The upper limit is hard-coded to 1000 for now, which should suffice for any practical usages up to now. Link: https://lore.kernel.org/r/20191106154257.5853-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/timer.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/sound/core/timer.c b/sound/core/timer.c index c60dfd52e8a6d..22589a073423b 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -88,6 +88,9 @@ static LIST_HEAD(snd_timer_slave_list); /* lock for slave active lists */ static DEFINE_SPINLOCK(slave_active_lock); +#define MAX_SLAVE_INSTANCES 1000 +static int num_slaves; + static DEFINE_MUTEX(register_mutex); static int snd_timer_free(struct snd_timer *timer); @@ -266,6 +269,10 @@ int snd_timer_open(struct snd_timer_instance **ti, err = -EINVAL; goto unlock; } + if (num_slaves >= MAX_SLAVE_INSTANCES) { + err = -EBUSY; + goto unlock; + } timeri = snd_timer_instance_new(owner, NULL); if (!timeri) { err = -ENOMEM; @@ -275,6 +282,7 @@ int snd_timer_open(struct snd_timer_instance **ti, timeri->slave_id = tid->device; timeri->flags |= SNDRV_TIMER_IFLG_SLAVE; list_add_tail(&timeri->open_list, &snd_timer_slave_list); + num_slaves++; err = snd_timer_check_slave(timeri); if (err < 0) { snd_timer_close_locked(timeri, &card_dev_to_put); @@ -364,6 +372,8 @@ static int snd_timer_close_locked(struct snd_timer_instance *timeri, struct snd_timer_instance *slave, *tmp; list_del(&timeri->open_list); + if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) + num_slaves--; /* force to stop the timer */ snd_timer_stop(timeri); -- 2.20.1