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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 8CB52C4727F for ; Tue, 29 Sep 2020 12:42:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E9D320725 for ; Tue, 29 Sep 2020 12:42:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601383339; bh=eiz7aoc8IANfM5Zam+W3qobqu1VmS3mANYdwlS2WVIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=daDq2/1VhAyRkwm38urr8obUsv7CLaotldgRYZXble0Mqd+ZEAzlmBJBRy9ZtVy6J VmLOkqcfzQzrg7oTLjYNxvMMKLmfIqooXQc+CIL0Og2FehY6QjCrAITn2qz6lonh5N xw+pmdoUXVi2HhAY9pRkUQGEhdkFrePjNCE14Xwo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729476AbgI2MmR (ORCPT ); Tue, 29 Sep 2020 08:42:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:53300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729271AbgI2LLu (ORCPT ); Tue, 29 Sep 2020 07:11:50 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C9768208FE; Tue, 29 Sep 2020 11:11:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601377910; bh=eiz7aoc8IANfM5Zam+W3qobqu1VmS3mANYdwlS2WVIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eo+VT7aUGXyTZqFzZcZvbE08kUeWCeAcD456QkQG4ClN7LGQxcAS52ZrjgqbBYNp8 LH9OFNtt03ykKNxo1EOBtvYTvGLGSTVoj3qsHFwJuxXQBQDUlErWEm+blkcXM63eZa zG+DSOfkR1NPpoEFTob6Xfp6/oijsUA9fPL0eEGA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 4.9 086/121] ALSA: hda: Fix potential race in unsol event handler Date: Tue, 29 Sep 2020 13:00:30 +0200 Message-Id: <20200929105934.438541203@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105930.172747117@linuxfoundation.org> References: <20200929105930.172747117@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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