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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D420CC001B0 for ; Mon, 24 Jul 2023 01:37:58 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id E6EA0E98; Mon, 24 Jul 2023 03:37:06 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz E6EA0E98 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1690162677; bh=omSorsWROY2XhObA/P2khsZpOVC+P+TZxcFELmq9keA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=GhAhB+4ekos3so/weHi+KH9giWF2kktgXBc0eBCOdeFGytn7ylXldbddFvGvJn2F1 OzDMQs0ui4CDkV+tTeEaN2YUZO7JiyV3MeLTnnFfbMMRKyoZdAjoK3wewiFe2lPcoz fVwivov/iOQ950KsogbHyAqTY2B08VIMWctDSFgk= Received: by alsa1.perex.cz (Postfix, from userid 50401) id E58AAF80601; Mon, 24 Jul 2023 03:34:31 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 4F16CF805FB; Mon, 24 Jul 2023 03:34:31 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 57925F80553; Mon, 24 Jul 2023 03:34:27 +0200 (CEST) Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 90787F80163 for ; Mon, 24 Jul 2023 03:34:25 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 90787F80163 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=UMeiGuXP 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 84E1D60F33; Mon, 24 Jul 2023 01:34:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10D6CC433CC; Mon, 24 Jul 2023 01:34:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162463; bh=omSorsWROY2XhObA/P2khsZpOVC+P+TZxcFELmq9keA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UMeiGuXPWkB7TQ8wCqeW7F0qM8iUrDtfuHJmI+8sTyc18peBhzKrWRT7ubErmVseh QqX6hpT9BlvyrHoQAQwN4+JqoxSNEAvRJTHnebvVn2FKjrmRLF/1cH/cMZwUvAX3KU uJwDF4syrT3yQa7MCgC+7A98bbz42PhjqfQrzMU7N1+Uty85+1Oaxh7psGwpoVKQCU MD5c+ipTwMFzNK/4cNemCDCrr2aGC9Ht66iXSuUE0jsk92GNH1ILhI5fG5qIsHZclL frayJbKl2vSj53rJXVaCMgTfKQi8T4DOrvPM9WZsO5Gwz0PSZpnMXBE/oXqwT4nuf1 Mv4QHXfRyMYtQ== 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 5.10 15/16] ALSA: hda: fix a possible null-pointer dereference due to data race in snd_hdac_regmap_sync() Date: Sun, 23 Jul 2023 21:33:59 -0400 Message-Id: <20230724013401.2333159-15-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013401.2333159-1-sashal@kernel.org> References: <20230724013401.2333159-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.186 Content-Transfer-Encoding: 8bit Message-ID-Hash: GCGKF7XXVZ6AZJEJJMJ3FQSXH5CZWN5X X-Message-ID-Hash: GCGKF7XXVZ6AZJEJJMJ3FQSXH5CZWN5X X-MailFrom: sashal@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: 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 d75f31eb9d78f..bf35acca5ea0e 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