[PATCH AUTOSEL 5.9 051/147] mmc: via-sdmmc: Fix data race bug

[Sasha Levin]

From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

[ Upstream commit 87d7ad089b318b4f319bf57f1daa64eb6d1d10ad ]

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@xxxxxxxxx>
Link: https://lore.kernel.org/r/20200822061528.7035-1-madhuparnabhowmik10@xxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 49dab9f42b6d6..9b755ea0fa03c 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);
 
-- 
2.25.1