mmc: sh-mmcif: avoid oops on spurious interrupts

On some systems, e.g., kzm9g, MMCIF interfaces can produce spurious
interrupts without any active request. To prevent the Oops, that results
in such cases, don't dereference the mmc request pointer until we make
sure, that we are indeed processing such a request.

Reported-by: Tetsuyuki Kobayashi <koba@kmckk.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 6df3dc3..11d2bc3 100644 (file)
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -1231,6 +1231,10 @@ static irqreturn_t sh_mmcif_intr(int irq, void *dev_id)
                host->sd_error = true;
                dev_dbg(&host->pd->dev, "int err state = %08x\n", state);
        }
+       if (host->state == STATE_IDLE) {
+               dev_info(&host->pd->dev, "Spurious IRQ status 0x%x", state);
+               return IRQ_HANDLED;
+       }
        if (state & ~(INT_CMD12RBE | INT_CMD12CRE)) {
                if (!host->dma_active)
                        return IRQ_WAKE_THREAD;