From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 599A2129EC7; Mon, 18 Dec 2023 14:09:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xVibD4F4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0264C433C7; Mon, 18 Dec 2023 14:09:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702908591; bh=v+kfDNWMiEp4qJDDmhXVc/mCnGAt+4f2HqS6jGRKXJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xVibD4F4wx/bmUSek97WUtSzCOewCPB97mzTaCGh9NsY4m9M8Vwef7N4nktAmEsfx bQRezgk6NzuHXaAkUheSEAIspXuJgAJmzrNo5YW+fwyZjjD/QacwIQV/Z4LROF90Yi 2xSrK/pGOlBFxdypAND3spD99r/MB2SeiS4U2mmI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Krzysztof Kozlowski , Pierre-Louis Bossart , Vinod Koul Subject: [PATCH 5.10 48/62] soundwire: stream: fix NULL pointer dereference for multi_link Date: Mon, 18 Dec 2023 14:52:12 +0100 Message-ID: <20231218135048.369726725@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218135046.178317233@linuxfoundation.org> References: <20231218135046.178317233@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Krzysztof Kozlowski commit e199bf52ffda8f98f129728d57244a9cd9ad5623 upstream. If bus is marked as multi_link, but number of masters in the stream is not higher than bus->hw_sync_min_links (bus->multi_link && m_rt_count >= bus->hw_sync_min_links), bank switching should not happen. The first part of do_bank_switch() code properly takes these conditions into account, but second part (sdw_ml_sync_bank_switch()) relies purely on bus->multi_link property. This is not balanced and leads to NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 ... Call trace: wait_for_completion_timeout+0x124/0x1f0 do_bank_switch+0x370/0x6f8 sdw_prepare_stream+0x2d0/0x438 qcom_snd_sdw_prepare+0xa0/0x118 sm8450_snd_prepare+0x128/0x148 snd_soc_link_prepare+0x5c/0xe8 __soc_pcm_prepare+0x28/0x1ec dpcm_be_dai_prepare+0x1e0/0x2c0 dpcm_fe_dai_prepare+0x108/0x28c snd_pcm_do_prepare+0x44/0x68 snd_pcm_action_single+0x54/0xc0 snd_pcm_action_nonatomic+0xe4/0xec snd_pcm_prepare+0xc4/0x114 snd_pcm_common_ioctl+0x1154/0x1cc0 snd_pcm_ioctl+0x54/0x74 Fixes: ce6e74d008ff ("soundwire: Add support for multi link bank switch") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski Reviewed-by: Pierre-Louis Bossart Link: https://lore.kernel.org/r/20231124180136.390621-1-krzysztof.kozlowski@linaro.org Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/soundwire/stream.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/soundwire/stream.c +++ b/drivers/soundwire/stream.c @@ -724,14 +724,15 @@ error_1: * sdw_ml_sync_bank_switch: Multilink register bank switch * * @bus: SDW bus instance + * @multi_link: whether this is a multi-link stream with hardware-based sync * * Caller function should free the buffers on error */ -static int sdw_ml_sync_bank_switch(struct sdw_bus *bus) +static int sdw_ml_sync_bank_switch(struct sdw_bus *bus, bool multi_link) { unsigned long time_left; - if (!bus->multi_link) + if (!multi_link) return 0; /* Wait for completion of transfer */ @@ -827,7 +828,7 @@ static int do_bank_switch(struct sdw_str bus->bank_switch_timeout = DEFAULT_BANK_SWITCH_TIMEOUT; /* Check if bank switch was successful */ - ret = sdw_ml_sync_bank_switch(bus); + ret = sdw_ml_sync_bank_switch(bus, multi_link); if (ret < 0) { dev_err(bus->dev, "multi link bank switch failed: %d\n", ret);