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 8952CC43464 for ; Fri, 18 Sep 2020 02:17:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D38A2396D for ; Fri, 18 Sep 2020 02:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395479; bh=eiz7aoc8IANfM5Zam+W3qobqu1VmS3mANYdwlS2WVIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bMiCyXTHGb6lJ0F45tEF7COdCwPU/XNDmd1c02Q+RsqyT2q48zrHcoJ39cmjqluTx 0zCW3O+d4yK7knPyzIqRl08h5mvkUcQ5qSIcFum4WNMcY3DC+8iSVgFH+kteFG+7bH jTFmhHow8L0vAKbQkfZRDJsxh2CesQSHIv4ydTCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729629AbgIRCR6 (ORCPT ); Thu, 17 Sep 2020 22:17:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:48720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729590AbgIRCRr (ORCPT ); Thu, 17 Sep 2020 22:17:47 -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 50621238EE; Fri, 18 Sep 2020 02:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395466; bh=eiz7aoc8IANfM5Zam+W3qobqu1VmS3mANYdwlS2WVIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kcAQpHWGOGfAIoGTX7UJzvpx+wtvbs9cvfvvdaIOcZ4NY4OBDM4MzLjm4H9O6Bz86 wfCe+EiJxzOPsbRiKygNO9AOZiXh65DHohAVckwsG/lIcCOw24VDcZhbK55tlK5lHs wsqBlgFNcqTxICz6erq5SBNUswo7HxPeSIRHoKjo= 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 4.4 52/64] ALSA: hda: Fix potential race in unsol event handler Date: Thu, 17 Sep 2020 22:16:31 -0400 Message-Id: <20200918021643.2067895-52-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021643.2067895-1-sashal@kernel.org> References: <20200918021643.2067895-1-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 0e81ea89a5965..e3f68a76d90eb 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