Re: [BUGFIX 2/2] gdth: bugfix for the Timer at exit crash

[Boaz Harrosh <bharrosh@panasas.com>]

On Tue, Feb 12 2008 at 19:40 +0200, Boaz Harrosh <bharrosh@panasas.com> wrote:
> gdth _exit would first remove all cards then stop the timer
> and would not sync with the timer function. This caused a crash
> in gdth_timer() when module was unloaded.
> 
> del_timer_sync the timer before we delete the cards.
> 
> NOT YET TESTED
> 
> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>

Tested-by: Stefan Priebe <s.priebe@allied-internet.ag>

> ---
>  drivers/scsi/gdth.c |   15 ++++++++-------
>  1 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
> index 8eb78be..103280e 100644
> --- a/drivers/scsi/gdth.c
> +++ b/drivers/scsi/gdth.c
> @@ -3793,6 +3793,8 @@ static void gdth_timeout(ulong data)
>      gdth_ha_str *ha;
>      ulong flags;
>  
> +    BUG_ON(list_empty(&gdth_instances));
> +
>      ha = list_first_entry(&gdth_instances, gdth_ha_str, list);
>      spin_lock_irqsave(&ha->smp_lock, flags);
>  
> @@ -5146,8 +5148,6 @@ static void gdth_remove_one(gdth_ha_str *ha)
>  		ha->sdev = NULL;
>  	}
>  
> -	gdth_flush(ha);
> -
>  	if (shp->irq)
>  		free_irq(shp->irq,ha);
>  
> @@ -5245,14 +5245,15 @@ static void __exit gdth_exit(void)
>  {
>  	gdth_ha_str *ha;
>  
> -	list_for_each_entry(ha, &gdth_instances, list)
> -		gdth_remove_one(ha);
> +	unregister_chrdev(major,"gdth");
> +	unregister_reboot_notifier(&gdth_notifier);
>  
>  #ifdef GDTH_STATISTICS
> -	del_timer(&gdth_timer);
> +	del_timer_sync(&gdth_timer);
>  #endif
> -	unregister_chrdev(major,"gdth");
> -	unregister_reboot_notifier(&gdth_notifier);
> +
> +	list_for_each_entry(ha, &gdth_instances, list)
> +		gdth_remove_one(ha);
>  }
>  
>  module_init(gdth_init);

James please put this patch in rc-fixes also. It has now been tested
by few people, and it solves a reproducible problem in the unloading
of the driver.

It was not yet confirmed by Andrew's reporter with the:
	+    if (list_empty(&gdth_instances))
	+	return;

at gdth_timer() In -mm tree. In my patch I have converted the if() to a 
BUG_ON because now it should not happen. But I figure it is not worse then 
what there is now, which is nothing.

With your recommendation I will push both patches to the stable branches
People have emailed me requesting it.

Thanks
Boaz