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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 5AD15C43465 for ; Fri, 18 Sep 2020 02:41:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 144BE2371F for ; Fri, 18 Sep 2020 02:41:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600396876; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=c2INrQMXKPPbHdpKC6RwbisLHRh/0ICJaDNrQCSHlj0OM165LGgX81uy63o/Rzv9n l3sZDh4r3lTqz7QL1zRf8EuMBGL5F6txeW4NY0poXRkx+R0ZnD0WwgG0J4DQuFpVWK zC/qcvQCWwHcZx4SWXGy1GJhLB+tUWPgXR79KF0k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728963AbgIRClL (ORCPT ); Thu, 17 Sep 2020 22:41:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:36682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728621AbgIRCLW (ORCPT ); Thu, 17 Sep 2020 22:11:22 -0400 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 0FA0023119; Fri, 18 Sep 2020 02:11:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395081; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bcG2zI2WjGyn6lrR6xhAPMa+tUkLu31zkcIDFE6Q6s10AKIinNXjd2Uj8mF0FuHPP rHuDzpVO7XFhLt5/jt3Diiv6i94NI20VbdTt+L6WhcnTRU1MFgya8Y4YefUZWCV+Nv U9tLB5ReJkmt/du7msN/Pzww2R5MWJmOvCr2w2WY= 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 4.19 164/206] ALSA: hda: Fix potential race in unsol event handler Date: Thu, 17 Sep 2020 22:07:20 -0400 Message-Id: <20200918020802.2065198-164-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020802.2065198-1-sashal@kernel.org> References: <20200918020802.2065198-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai [ Upstream commit c637fa151259c0f74665fde7cba5b7eac1417ae5 ] The unsol event handling code has a loop retrieving the read/write indices and the arrays without locking while the append to the array may happen concurrently. This may lead to some inconsistency. Although there hasn't been any proof of this bad results, it's still safer to protect the racy accesses. This patch adds the spinlock protection around the unsol handling loop for addressing it. Here we take bus->reg_lock as the writer side snd_hdac_bus_queue_event() is also protected by that lock. Link: https://lore.kernel.org/r/20200516062556.30951-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/hda/hdac_bus.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/hda/hdac_bus.c b/sound/hda/hdac_bus.c index 714a51721a313..ab9236e4c157e 100644 --- a/sound/hda/hdac_bus.c +++ b/sound/hda/hdac_bus.c @@ -155,6 +155,7 @@ static void process_unsol_events(struct work_struct *work) struct hdac_driver *drv; unsigned int rp, caddr, res; + spin_lock_irq(&bus->reg_lock); while (bus->unsol_rp != bus->unsol_wp) { rp = (bus->unsol_rp + 1) % HDA_UNSOL_QUEUE_SIZE; bus->unsol_rp = rp; @@ -166,10 +167,13 @@ static void process_unsol_events(struct work_struct *work) codec = bus->caddr_tbl[caddr & 0x0f]; if (!codec || !codec->dev.driver) continue; + spin_unlock_irq(&bus->reg_lock); drv = drv_to_hdac_driver(codec->dev.driver); if (drv->unsol_event) drv->unsol_event(codec, res); + spin_lock_irq(&bus->reg_lock); } + spin_unlock_irq(&bus->reg_lock); } /** -- 2.25.1