[PATCH v2] drivers: mmc: host: via-sdmmc: Fix data race bug

From: madhuparnabhowmik10@gmail.com
To: brucechang@via.com.tw, HaraldWelte@viatech.com, ulf.hansson@linaro.org
Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	andrianov@ispras.ru, ldv-project@linuxtesting.org,
	Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Subject: [PATCH v2] drivers: mmc: host: via-sdmmc: Fix data race bug
Date: Sat, 22 Aug 2020 11:45:28 +0530	[thread overview]
Message-ID: <20200822061528.7035-1-madhuparnabhowmik10@gmail.com> (raw)

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

via_save_pcictrlreg() should be called with host->lock held
as it writes to pm_pcictrl_reg, otherwise there can be a race
condition between via_sd_suspend() and via_sdc_card_detect().
The same pattern is used in the function via_reset_pcictrl()
as well, where via_save_pcictrlreg() is called with host->lock
held.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
v2: Rebase v5.9-rc1

 drivers/mmc/host/via-sdmmc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
index 49dab9f42b6d..9b755ea0fa03 100644
--- a/drivers/mmc/host/via-sdmmc.c
+++ b/drivers/mmc/host/via-sdmmc.c
@@ -1257,11 +1257,14 @@ static void __maybe_unused via_init_sdc_pm(struct via_crdr_mmc_host *host)
 static int __maybe_unused via_sd_suspend(struct device *dev)
 {
 	struct via_crdr_mmc_host *host;
+	unsigned long flags;
 
 	host = dev_get_drvdata(dev);
 
+	spin_lock_irqsave(&host->lock, flags);
 	via_save_pcictrlreg(host);
 	via_save_sdcreg(host);
+	spin_unlock_irqrestore(&host->lock, flags);
 
 	device_wakeup_enable(dev);
 
-- 
2.17.1

