Re: [PATCH 3/5] MTD: blktrans: fix a race vs kthread_stop.

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2010-10-15 at 17:20 +0200, Maxim Levitsky wrote:
> There is small race window that could make kthread_stop hang forever.
> I found that while hacking the IR subsystem.
> 
> Signed-off-by: Maxim Levitsky <maximlevisky@gmail.com>
> ---
>  drivers/mtd/mtd_blkdevs.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
> index 040c2d9..a919587 100644
> --- a/drivers/mtd/mtd_blkdevs.c
> +++ b/drivers/mtd/mtd_blkdevs.c
> @@ -133,6 +133,10 @@ static int mtd_blktrans_thread(void *arg)
>  
>  		if (!req && !(req = blk_fetch_request(rq))) {
>  			set_current_state(TASK_INTERRUPTIBLE);
> +
> +			if (kthread_should_stop())
> +				set_current_state(TASK_RUNNING);
> +
>  			spin_unlock_irq(rq->queue_lock);
>  			schedule();
>  			spin_lock_irq(rq->queue_lock);


Shouldn't we add a break in there too, so it immediately breaks out of
the loop (with the lock held)?

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation