On Fri, Nov 08, 2024 at 08:01:12AM +0100, Jan Kiszka wrote:
> On 06.11.24 13:01, Greg Kroah-Hartman wrote:
> > 6.11-stable review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Wander Lairson Costa <wander@xxxxxxxxxx>
> >
> > [ Upstream commit 338c4d3902feb5be49bfda530a72c7ab860e2c9f ]
> >
> > During testing of SR-IOV, Red Hat QE encountered an issue where the
> > ip link up command intermittently fails for the igbvf interfaces when
> > using the PREEMPT_RT variant. Investigation revealed that
> > e1000_write_posted_mbx returns an error due to the lack of an ACK
> > from e1000_poll_for_ack.
> >
> > The underlying issue arises from the fact that IRQs are threaded by
> > default under PREEMPT_RT. While the exact hardware details are not
> > available, it appears that the IRQ handled by igb_msix_other must
> > be processed before e1000_poll_for_ack times out. However,
> > e1000_write_posted_mbx is called with preemption disabled, leading
> > to a scenario where the IRQ is serviced only after the failure of
> > e1000_write_posted_mbx.
> >
> > To resolve this, we set IRQF_NO_THREAD for the affected interrupt,
> > ensuring that the kernel handles it immediately, thereby preventing
> > the aforementioned error.
> >
> > Reproducer:
> >
> > #!/bin/bash
> >
> > # echo 2 > /sys/class/net/ens14f0/device/sriov_numvfs
> > ipaddr_vlan=3
> > nic_test=ens14f0
> > vf=${nic_test}v0
> >
> > while true; do
> > ip link set ${nic_test} mtu 1500
> > ip link set ${vf} mtu 1500
> > ip link set $vf up
> > ip link set ${nic_test} vf 0 vlan ${ipaddr_vlan}
> > ip addr add 172.30.${ipaddr_vlan}.1/24 dev ${vf}
> > ip addr add 2021:db8:${ipaddr_vlan}::1/64 dev ${vf}
> > if ! ip link show $vf | grep 'state UP'; then
> > echo 'Error found'
> > break
> > fi
> > ip link set $vf down
> > done
> >
> > Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
> > Fixes: 9d5c824399de ("igb: PCI-Express 82575 Gigabit Ethernet driver")
> > Reported-by: Yuying Ma <yuma@xxxxxxxxxx>
> > Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>
> > Tested-by: Rafal Romanowski <rafal.romanowski@xxxxxxxxx>
> > Signed-off-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
> > Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> > Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> > drivers/net/ethernet/intel/igb/igb_main.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> > index f1d0881687233..b83df5f94b1f5 100644
> > --- a/drivers/net/ethernet/intel/igb/igb_main.c
> > +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> > @@ -907,7 +907,7 @@ static int igb_request_msix(struct igb_adapter *adapter)
> > int i, err = 0, vector = 0, free_vector = 0;
> >
> > err = request_irq(adapter->msix_entries[vector].vector,
> > - igb_msix_other, 0, netdev->name, adapter);
> > + igb_msix_other, IRQF_NO_THREAD, netdev->name, adapter);
> > if (err)
> > goto err_out;
> >
>
> This is scheduled for being reverted upstream [1]. Please drop from all
> stable queues.
Now dropped from all of them, thanks.
greg k-h
