[PATCH] powerpc/eeh: check handle_eeh_events() return value

[Benjamin Herrenschmidt]

On Fri, 2012-07-13 at 00:14 -0300, Kleber Sacilotto de Souza wrote:
> Function eeh_event_handler() dereferences the pointer returned by
> handle_eeh_events() without checking, causing a crash if NULL was
> returned, which is expected in some situations.
> 
> This patch fixes this bug by checking for the value returned by
> handle_eeh_events() before dereferencing it.

Thanks,
Ben.

> Signed-off-by: Kleber Sacilotto de Souza <klebers at linux.vnet.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/eeh_event.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/eeh_event.c b/arch/powerpc/platforms/pseries/eeh_event.c
> index 4cb375c..fb50631 100644
> --- a/arch/powerpc/platforms/pseries/eeh_event.c
> +++ b/arch/powerpc/platforms/pseries/eeh_event.c
> @@ -85,8 +85,10 @@ static int eeh_event_handler(void * dummy)
>  	set_current_state(TASK_INTERRUPTIBLE);	/* Don't add to load average */
>  	edev = handle_eeh_events(event);
>  
> -	eeh_clear_slot(eeh_dev_to_of_node(edev), EEH_MODE_RECOVERING);
> -	pci_dev_put(edev->pdev);
> +	if (edev) {
> +		eeh_clear_slot(eeh_dev_to_of_node(edev), EEH_MODE_RECOVERING);
> +		pci_dev_put(edev->pdev);
> +	}
>  
>  	kfree(event);
>  	mutex_unlock(&eeh_event_mutex);