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From:   Johan Hovold <johan+linaro@kernel.org>
To:     Mark Brown <broonie@kernel.org>, Vinod Koul <vkoul@kernel.org>
Cc:     Bard Liao <yung-chuan.liao@linux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Sanyog Kale <sanyog.r.kale@intel.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Banajit Goswami <bgoswami@quicinc.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org,
        Johan Hovold <johan+linaro@kernel.org>, stable@vger.kernel.org,
        Rander Wang <rander.wang@linux.intel.com>
Subject: [PATCH 1/8] soundwire: fix enumeration completion
Date:   Wed,  5 Jul 2023 14:30:11 +0200
Message-Id: <20230705123018.30903-2-johan+linaro@kernel.org>
In-Reply-To: <20230705123018.30903-1-johan+linaro@kernel.org>
References: <20230705123018.30903-1-johan+linaro@kernel.org>
MIME-Version: 1.0
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The soundwire subsystem uses two completion structures that allow
drivers to wait for soundwire device to become enumerated on the bus and
initialised by their drivers, respectively.

The code implementing the signalling is currently broken as it does not
signal all current and future waiters and also uses the wrong
reinitialisation function, which can potentially lead to memory
corruption if there are still waiters on the queue.

Not signalling future waiters specifically breaks sound card probe
deferrals as codec drivers can not tell that the soundwire device is
already attached when being reprobed. Some codec runtime PM
implementations suffer from similar problems as waiting for enumeration
during resume can also timeout despite the device already having been
enumerated.

Fixes: fb9469e54fa7 ("soundwire: bus: fix race condition with enumeration_complete signaling")
Fixes: a90def068127 ("soundwire: bus: fix race condition with initialization_complete signaling")
Cc: stable@vger.kernel.org      # 5.7
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/soundwire/bus.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 1ea6a64f8c4a..66e5dba919fa 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -908,8 +908,8 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
 			"initializing enumeration and init completion for Slave %d\n",
 			slave->dev_num);
 
-		init_completion(&slave->enumeration_complete);
-		init_completion(&slave->initialization_complete);
+		reinit_completion(&slave->enumeration_complete);
+		reinit_completion(&slave->initialization_complete);
 
 	} else if ((status == SDW_SLAVE_ATTACHED) &&
 		   (slave->status == SDW_SLAVE_UNATTACHED)) {
@@ -917,7 +917,7 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
 			"signaling enumeration completion for Slave %d\n",
 			slave->dev_num);
 
-		complete(&slave->enumeration_complete);
+		complete_all(&slave->enumeration_complete);
 	}
 	slave->status = status;
 	mutex_unlock(&bus->bus_lock);
@@ -1941,7 +1941,7 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
 				"signaling initialization completion for Slave %d\n",
 				slave->dev_num);
 
-			complete(&slave->initialization_complete);
+			complete_all(&slave->initialization_complete);
 
 			/*
 			 * If the manager became pm_runtime active, the peripherals will be
-- 
2.39.3