mmc: via-sdmmc: Fix data race bug

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>
Link: https://lore.kernel.org/r/20200822061528.7035-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
index 49dab9f..9b755ea 100644 (file)
--- 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);