Re: [dpdk-dev] [PATCH] net/ixgbe: fix cancel link handler when port is being removed

[wangyunjian <wangyunjian@huawei.com>]

> -----Original Message-----
> From: Zhao1, Wei [mailto:wei.zhao1@intel.com]
> Sent: Friday, May 10, 2019 11:14 AM
> To: wangyunjian <wangyunjian@huawei.com>; dev@dpdk.org
> Cc: i.maximets@samsung.com; xudingke <xudingke@huawei.com>;
> stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] net/ixgbe: fix cancel link handler when port
> is being removed
> 
> Hi,  wangyunjian
> 
>  	May I ask some more info about it?
> Sure, we may this handler in ixgbe_dev_link_update_share (),  but we have
> "rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler, dev)"
> in function ixgbe_dev_stop() and ixgbevf_dev_stop() to  cancel this handler.
> If you want to remove dev, you will call ixgbe_dev_stop() first, RIGHT?
> Maybe there is an accidental situation that some interrupt like LSC trigger
> ixgbe_dev_link_update() to set setup_link_alarm_handler just after dev stop?
> Then we need to cancel it in eth_ixgbe_dev_uninit().
> Is you issue the same as above or other?

Yes,  it is as above. It is easy to reproduce through fault injection. As follow:

diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
index 975fa47..a1e93c0 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.c
+++ b/drivers/net/ixgbe/ixgbe_ethdev.c
@@ -4055,7 +4055,7 @@ static int ixgbevf_dev_xstats_get_names(__rte_unused struct rte_eth_dev *dev,
        if (link_up == 0) {
                if (ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
                        intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
-                       rte_eal_alarm_set(10,
+                       rte_eal_alarm_set(500 * 1000,
                                ixgbe_dev_setup_link_alarm_handler, dev);
                }
                return rte_eth_linkstatus_set(dev, &link);

> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of wangyunjian
> > Sent: Wednesday, May 8, 2019 8:52 PM
> > To: dev@dpdk.org
> > Cc: i.maximets@samsung.com; xudingke@huawei.com; Yunjian Wang
> > <wangyunjian@huawei.com>; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH] net/ixgbe: fix cancel link handler when
> > port is being removed
> >
> > From: Yunjian Wang <wangyunjian@huawei.com>
> >
> > The nic's interrupt source has some active handler, which maybe call
> > ixgbe_dev_link_update() to set link handler. We should cancel the link
> > handler before remove dev to prevent executing the link handler.
> > It triggers segfault.
> >
> > Fixes: 0408f47ba4d6 ("net/ixgbe: fix busy polling while fiber link
> > update")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> > b/drivers/net/ixgbe/ixgbe_ethdev.c
> > index 975fa47..2470c89 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -1344,6 +1344,9 @@ struct rte_ixgbe_xstats_name_off {
> >  	/* cancel the delay handler before remove dev */
> >  	rte_eal_alarm_cancel(ixgbe_dev_interrupt_delayed_handler,
> eth_dev);
> >
> > +	/* cancel the link handler before remove dev */
> > +	rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler,
> eth_dev);
> > +
> >  	/* uninitialize PF if max_vfs not zero */
> >  	ixgbe_pf_host_uninit(eth_dev);
> >
> > --
> > 1.8.3.1
> >