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

From: Boaz Harrosh
Date: Wed Feb 13 2008 - 05:50:48 EST


On Tue, Feb 12 2008 at 19:40 +0200, Boaz Harrosh <bharrosh@xxxxxxxxxxx> 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@xxxxxxxxxxx>

Tested-by: Stefan Priebe <s.priebe@xxxxxxxxxxxxxxxxxx>

> ---
> 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

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