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Subject[PATCH] mmc: core: Fix struct mmc_gpio corruption
Date
I recently realised that something was amiss with /proc/interrupts
on my cubietruck:

51: 0 0 GICv2 41 Level mv64xxx_i2c
59: 1047 0 GICv2 117 Level eth0
66: 2 0 sunxi_pio_edge 1 Edge XXXXX

where XXXXX has some non-ASCII characters, while I was expecting:

66: 0 0 sunxi_pio_edge 1 Edge 1c0f000.mmc cd

It turns out that the cd_debounce_delay_ms field was recently to
struct mmc_gpio, and carefully placed at the one spot where it could
cause damage: right *after* the zero-sized array that contains the
associated label. This label ends up being passed to the IRQ
subsystem, and then overwritten by the cd_debounce_delay_ms field.

Funky!

Let's move that field to a less crowded location.

Fixes: bfd694d5e21c ("mmc: core: Add tunable delay before detecting card after card is inserted")
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/mmc/core/slot-gpio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
index ef05e0039378..1ccf9dc07395 100644
--- a/drivers/mmc/core/slot-gpio.c
+++ b/drivers/mmc/core/slot-gpio.c
@@ -27,8 +27,8 @@ struct mmc_gpio {
bool override_cd_active_level;
irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
char *ro_label;
- char cd_label[0];
u32 cd_debounce_delay_ms;
+ char cd_label[0];
};

static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
--
2.17.1
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