[PATCH v2] moxart: fix potential use-after-free on remove path

[Greg Kroah-Hartman]

It was reported that the mmc host structure could be accessed after it
was freed in moxart_remove(), so fix this by saving the base register of
the device and using it instead of the pointer dereference.

Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Cc: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Cc: Xin Xiong <xiongx18@xxxxxxxxxxxx>
Cc: Xin Tan <tanxin.ctf@xxxxxxxxx>
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Yang Li <yang.lee@xxxxxxxxxxxxxxxxx>
Cc: linux-mmc@xxxxxxxxxxxxxxx
Cc: stable <stable@xxxxxxxxxxxxxxx>
Reported-by: whitehat002 <hackyzh002@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
v2: changed to only move mmc_free_host() call as per Ulf's request

 drivers/mmc/host/moxart-mmc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
index 16d1c7a43d33..b6eb75f4bbfc 100644
--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -705,12 +705,12 @@ static int moxart_remove(struct platform_device *pdev)
 	if (!IS_ERR_OR_NULL(host->dma_chan_rx))
 		dma_release_channel(host->dma_chan_rx);
 	mmc_remove_host(mmc);
-	mmc_free_host(mmc);
 
 	writel(0, host->base + REG_INTERRUPT_MASK);
 	writel(0, host->base + REG_POWER_CONTROL);
 	writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
 	       host->base + REG_CLOCK_CONTROL);
+	mmc_free_host(mmc);
 
 	return 0;
 }
-- 
2.35.0