mmc: sh-mmcif: avoid oops on spurious interrupts

commit 8464dd52d3198dd05cafb005371d76e5339eb842 upstream.

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>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 5d8142773fac073b75cf56db111ecde2d398717d..ba0e493ad0c603d42918cb227a6335d5c1d27fc5 100644 (file)
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -1229,6 +1229,10 @@ 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;