4.9-stable patches

[thirdparty/kernel/stable-queue.git] / releases / 3.6.2 / mmc-sh-mmcif-avoid-oops-on-spurious-interrupts.patch

From 8464dd52d3198dd05cafb005371d76e5339eb842 Mon Sep 17 00:00:00 2001
From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Date: Tue, 18 Sep 2012 06:42:42 +0000
Subject: mmc: sh-mmcif: avoid oops on spurious interrupts

From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>

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>

---
 drivers/mmc/host/sh_mmcif.c |    4 ++++
 1 file changed, 4 insertions(+)

--- 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
 		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;