Re: [RFC PATCH net 2/2] [BUGFIX] bonding: use flush_delayed_work_syncin bond_close

From: AmÃrico Wang
Date: Fri Oct 07 2011 - 09:34:35 EST


On Fri, Oct 7, 2011 at 8:50 PM, Mitsuo Hayasaka
<mitsuo.hayasaka.hu@xxxxxxxxxxx> wrote:
> The bond_close() calls cancel_delayed_work() to cancel delayed works.
> It, however, cannot cancel works that were already queued in workqueue.
> The bond_open() initializes work->data, and proccess_one_work() refers
> get_work_cwq(work)->wq->flags. The get_work_cwq() returns NULL when
> work->data has been initialized. Thus, a panic occurs.
>
> This patch uses flush_delayed_work_sync() instead of cancel_delayed_work()
> in bond_close(). It cancels delayed timer and waits for work to finish
> execution. So, it can avoid the null pointer dereference due to the
> parallel executions of proccess_one_work() and initializing proccess
> of bond_open().
>
> Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@xxxxxxxxxxx>
> Cc: Jay Vosburgh <fubar@xxxxxxxxxx>
> Cc: Andy Gospodarek <andy@xxxxxxxxxxxxx>

Makes sense,

Reviewed-by: WANG Cong <xiyou.wangcong@xxxxxxxxx>

Thanks!
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