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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E92ACC001B0 for ; Mon, 24 Jul 2023 01:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232107AbjGXBlv (ORCPT ); Sun, 23 Jul 2023 21:41:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231404AbjGXBk7 (ORCPT ); Sun, 23 Jul 2023 21:40:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBABA46BF; Sun, 23 Jul 2023 18:36:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2F1CB60F1B; Mon, 24 Jul 2023 01:32:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5BB9C433CB; Mon, 24 Jul 2023 01:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162347; bh=jq8SHtkpLjhWwKStwEjQuJaMiOn/KEjf21wr7/La3vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mvzzTlsCeDeCbkI6Jflng42kOMwjY5w1sCFWDvwV2CAuzRd+2GfADm8gj9nF0ZOiK jVQ4uv2ejxWnXdAHtHf2c9oIwgPZFjYHcPuEV+Lkd3vtbt5IBxRU9EJFTLWQUDKGpT Y+uLBtR9546FE0y1x6WAMe33o1LoWNzekHFdKGLEprJerU8Y7GicSwadA1MS5k2vQE 7XPhXh7mihlMY+I0JlOmMS3loCCIH2lW7aL0O6iFrO/FN5LtZdcRtEGYVbW+8Q3mHI T4JfIdOZbFoMT2cD6tx8pnahHjU12j+PcbQUmt7drHqxgbPXDq4U51mlIcWRJEivoC qpT/9UZrF9C4w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tuo Li , BassCheck , Takashi Iwai , Sasha Levin , perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 6.4 34/40] ALSA: hda: fix a possible null-pointer dereference due to data race in snd_hdac_regmap_sync() Date: Sun, 23 Jul 2023 21:31:34 -0400 Message-Id: <20230724013140.2327815-34-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013140.2327815-1-sashal@kernel.org> References: <20230724013140.2327815-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.5 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tuo Li [ Upstream commit 1f4a08fed450db87fbb5ff5105354158bdbe1a22 ] The variable codec->regmap is often protected by the lock codec->regmap_lock when is accessed. However, it is accessed without holding the lock when is accessed in snd_hdac_regmap_sync(): if (codec->regmap) In my opinion, this may be a harmful race, because if codec->regmap is set to NULL right after the condition is checked, a null-pointer dereference can occur in the called function regcache_sync(): map->lock(map->lock_arg); --> Line 360 in drivers/base/regmap/regcache.c To fix this possible null-pointer dereference caused by data race, the mutex_lock coverage is extended to protect the if statement as well as the function call to regcache_sync(). [ Note: the lack of the regmap_lock itself is harmless for the current codec driver implementations, as snd_hdac_regmap_sync() is only for PM runtime resume that is prohibited during the codec probe. But the change makes the whole code more consistent, so it's merged as is -- tiwai ] Reported-by: BassCheck Signed-off-by: Tuo Li Link: https://lore.kernel.org/r/20230703031016.1184711-1-islituo@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/hda/hdac_regmap.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/sound/hda/hdac_regmap.c b/sound/hda/hdac_regmap.c index fe3587547cfec..39610a15bcc98 100644 --- a/sound/hda/hdac_regmap.c +++ b/sound/hda/hdac_regmap.c @@ -597,10 +597,9 @@ EXPORT_SYMBOL_GPL(snd_hdac_regmap_update_raw_once); */ void snd_hdac_regmap_sync(struct hdac_device *codec) { - if (codec->regmap) { - mutex_lock(&codec->regmap_lock); + mutex_lock(&codec->regmap_lock); + if (codec->regmap) regcache_sync(codec->regmap); - mutex_unlock(&codec->regmap_lock); - } + mutex_unlock(&codec->regmap_lock); } EXPORT_SYMBOL_GPL(snd_hdac_regmap_sync); -- 2.39.2