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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 026/117] mmc: via-sdmmc: Fix data race bug
Date:   Mon,  9 Nov 2020 13:54:12 +0100
Message-Id: <20201109125026.896527896@linuxfoundation.org>
In-Reply-To: <20201109125025.630721781@linuxfoundation.org>
References: <20201109125025.630721781@linuxfoundation.org>
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From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ 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@gmail.com>
Link: https://lore.kernel.org/r/20200822061528.7035-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 63fac78b3d46a..b455e9cf95afc 100644
--- a/drivers/mmc/host/via-sdmmc.c
+++ b/drivers/mmc/host/via-sdmmc.c
@@ -1269,11 +1269,14 @@ static void via_init_sdc_pm(struct via_crdr_mmc_host *host)
 static int via_sd_suspend(struct pci_dev *pcidev, pm_message_t state)
 {
 	struct via_crdr_mmc_host *host;
+	unsigned long flags;
 
 	host = pci_get_drvdata(pcidev);
 
+	spin_lock_irqsave(&host->lock, flags);
 	via_save_pcictrlreg(host);
 	via_save_sdcreg(host);
+	spin_unlock_irqrestore(&host->lock, flags);
 
 	pci_save_state(pcidev);
 	pci_enable_wake(pcidev, pci_choose_state(pcidev, state), 0);
-- 
2.27.0