On Thu, 14 May 2015, Qiao Zhou wrote:
> On 05/14/2015 06:31 PM, Dan Carpenter wrote:
> >Hello Qiao Zhou,
> >
> >The patch 70c6cce04066: "mfd: Support 88pm80x in 80x driver" from Jul
> >9, 2012, leads to the following static checker warning:
> >
> > include/linux/mfd/88pm80x.h:352 pm80x_dev_suspend()
> > warn: test_bit() takes a bit number
> >
> >include/linux/mfd/88pm80x.h
> > 344 #ifdef CONFIG_PM
> > 345 static inline int pm80x_dev_suspend(struct device *dev)
> > 346 {
> > 347 struct platform_device *pdev = to_platform_device(dev);
> > 348 struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> > 349 int irq = platform_get_irq(pdev, 0);
> > 350
> > 351 if (device_may_wakeup(dev))
> > 352 set_bit((1 << irq), &chip->wu_flag);
> > ^^^^^^^^^
> >Smatch is complaining because it's doing a double left shift. If irq is
> >larger than 5 then we are corrupting memory. Also we don't use
> Will fix this issue.
> >->wu_flag as a bitfield, we use it as a boolean so the name is
> >confusing.
> >
> > 353
> > 354 return 0;
> > 355 }
> > 356
> > 357 static inline int pm80x_dev_resume(struct device *dev)
> > 358 {
> > 359 struct platform_device *pdev = to_platform_device(dev);
> > 360 struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> > 361 int irq = platform_get_irq(pdev, 0);
> > 362
> > 363 if (device_may_wakeup(dev))
> > 364 clear_bit((1 << irq), &chip->wu_flag);
> > ^^^^^^^^^^
> >Same issue.
> >
> > 365
> > 366 return 0;
> > 367 }
> > 368 #endif
> >
> >drivers/mfd/88pm80x.c
> > 133 #ifdef CONFIG_PM_SLEEP
> > 134 static int pm80x_suspend(struct device *dev)
> > 135 {
> > 136 struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> > 137 struct pm80x_chip *chip = i2c_get_clientdata(client);
> > 138
> > 139 if (chip && chip->wu_flag)
> > ^^^^^^^^^^^^^
> >Here it is used as a bool.
> It's designed in this way that sub device driver may use this flag.
> Also the bit value can tell which sub device sets the flag. However
> here we just check whether any bit is set.
> >
> > 140 if (device_may_wakeup(chip->dev))
> > 141 enable_irq_wake(chip->irq);
> > 142
> > 143 return 0;
> > 144 }
> > 145
> > 146 static int pm80x_resume(struct device *dev)
> > 147 {
> > 148 struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> > 149 struct pm80x_chip *chip = i2c_get_clientdata(client);
> > 150
> > 151 if (chip && chip->wu_flag)
> > ^^^^^^^^^^^^^
> >This is the only other user.
> >
> > 152 if (device_may_wakeup(chip->dev))
> > 153 disable_irq_wake(chip->irq);
> > 154
> > 155 return 0;
> > 156 }
> > 157 #endif
> >
> >
> >regards,
> >dan carpenter
> >
> Dan,
>
> Below is the patch to fix this issue. Please have a check and I'll
> submit an official patch to community after you reviewed. Thanks for
> finding this issue.
>
> From 96486fda25414e3b926c275b951ac1408fae7830 Mon Sep 17 00:00:00 2001
> From: Qiao Zhou <zhouqiao@xxxxxxxxxxx>
> Date: Thu, 14 May 2015 19:00:39 +0800
> Subject: [PATCH] mfd: 88pm80x: refine irq bit operation
>
> Set_bit/clear_bit for wu_flag may be corrupted if irq > 5(or 6 for
> aarch64). The maximum irq number from 88pm80x chip series is 24.
> Here we refine the code to protect the potential memory corruption.
>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Qiao Zhou <zhouqiao@xxxxxxxxxxx>
> ---
> include/linux/mfd/88pm80x.h | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mfd/88pm80x.h b/include/linux/mfd/88pm80x.h
> index 97cb283..a8c0318 100644
> --- a/include/linux/mfd/88pm80x.h
> +++ b/include/linux/mfd/88pm80x.h
> @@ -348,8 +348,14 @@ static inline int pm80x_dev_suspend(struct device *dev)
> struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> int irq = platform_get_irq(pdev, 0);
>
> + if ((irq < 0) || (irq >= 24)) {
irq > 23
Or, even better:
#include PM80X_MAX_IRQS 23
if (irq < 0 || irq > PM80X_MAX_IRQS) {
Drop the parentheses.
> + dev_err(dev, "pm80x: wrong irq 0x%x\n", irq);
No need to put pm80x, dev_err() will do that for you.
s/wrong irq/Invalid IRQ/
Is it really better in hex?
> + /* return 0, and do not block suspend */
This comment is not required.
> + return 0;
> + }
> +
> if (device_may_wakeup(dev))
> - set_bit((1 << irq), &chip->wu_flag);
> + set_bit(irq, &chip->wu_flag);
Can you come up with a better name?
> return 0;
> }
> @@ -360,8 +366,14 @@ static inline int pm80x_dev_resume(struct device *dev)
> struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> int irq = platform_get_irq(pdev, 0);
>
> + if ((irq < 0) || (irq >= 24)) {
> + dev_err(dev, "pm80x: wrong irq 0x%x\n", irq);
> +
Superfluous '\n'.
> + return 0;
> + }
> +
> if (device_may_wakeup(dev))
> - clear_bit((1 << irq), &chip->wu_flag);
> + clear_bit(irq, &chip->wu_flag);
>
> return 0;
> }
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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