RE: [PATCH] rtc-tps65910: fix invalid pointer access on _remove()

[Venu Byravarasu]

> -----Original Message-----
> From: Kim, Milo [mailto:Milo.Kim@xxxxxx]
> Sent: Thursday, November 29, 2012 7:36 AM
> To: Andrew Morton
> Cc: a.zummo@xxxxxxxxxxxx; swarren@xxxxxxxxxxxxx; Venu Byravarasu;
> Sivaram Nair; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] rtc-tps65910: fix invalid pointer access on _remove()
> 
>  The tps65910_rtc data is registered as the platform driver data in _probe().
>  Therefore the tps65910_rtc should be used on unregistering the rtc device.
>  And device pointer should be retrieved from the platform_device structure.
> 
>  This patch fixes the error as below.
> 
>  Unable to handle kernel NULL pointer dereference at virtual address
> 00000008
>  Modules linked in: rtc_tps65910(-)
>  CPU: 0    Not tainted  (3.7.0-rc7-next-20121128-g6b1f974-dirty #7)
>  PC is at tps65910_rtc_alarm_irq_enable+0x20/0x2c [rtc_tps65910]
>  LR is at tps65910_rtc_alarm_irq_enable+0x10/0x2c [rtc_tps65910]
>  [<bf000044>] (tps65910_rtc_alarm_irq_enable+0x20/0x2c [rtc_tps65910])
> from
>    [<bf0004d4>] (tps65910_rtc_remove+0x18/0x28 [rtc_)
>  [<bf0004d4>] (tps65910_rtc_remove+0x18/0x28 [rtc_tps65910]) from
>    [<c034e700>] (platform_drv_remove+0x18/0x1c)
>  [<c034e700>] (platform_drv_remove+0x18/0x1c) from
>    [<c034ceec>] (__device_release_driver+0x70/0xcc)
>  [<c034ceec>] (__device_release_driver+0x70/0xcc) from
>    [<c034d608>] (driver_detach+0xb4/0xb8)
>  [<c034d608>] (driver_detach+0xb4/0xb8) from
>    [<c034cc24>] (bus_remove_driver+0x7c/0xc0)
>  [<c034cc24>] (bus_remove_driver+0x7c/0xc0) from
>    [<c00a045c>] (sys_delete_module+0x148/0x21c)
>  [<c00a045c>] (sys_delete_module+0x148/0x21c) from
>    [<c0013c60>] (ret_fast_syscall+0x0/0x3c)
> 
> Signed-off-by: Milo(Woogyom) Kim <milo.kim@xxxxxx>
> ---
>  drivers/rtc/rtc-tps65910.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
> index e8d44bc..687006f 100644
> --- a/drivers/rtc/rtc-tps65910.c
> +++ b/drivers/rtc/rtc-tps65910.c
> @@ -288,11 +288,11 @@ static int __devinit tps65910_rtc_probe(struct
> platform_device *pdev)
>  static int __devexit tps65910_rtc_remove(struct platform_device *pdev)
>  {
>  	/* leave rtc running, but disable irqs */
> -	struct rtc_device *rtc = platform_get_drvdata(pdev);
> +	struct tps65910_rtc *tps_rtc = platform_get_drvdata(pdev);
> 
> -	tps65910_rtc_alarm_irq_enable(&rtc->dev, 0);
> +	tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);
> 
> -	rtc_device_unregister(rtc);
> +	rtc_device_unregister(tps_rtc->rtc);
>  	return 0;
>  }
> 
> --
> 1.7.9.5
> 
> 
> Best Regards,
> Milo

This change looks good to me.
Plz consider my ACK.
Acked-by: Venu Byravarasu <vbyravarasu@xxxxxxxxxx>
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