RE: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items

["Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>]

> -----Original Message-----
> From: Dexuan Cui
> Sent: Tuesday, March 6, 2018 10:22 AM
> To: bhelgaas@google.com; linux-pci@vger.kernel.org; KY Srinivasan <kys@microsoft.com>;
> Stephen Hemminger <sthemmin@microsoft.com>; olaf@aepfle.de; apw@canonical.com;
> jasowang@redhat.com
> Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org; Haiyang Zhang
> <haiyangz@microsoft.com>; vkuznets@redhat.com; marcelo.cerri@canonical.com; Michael
> Kelley (EOSG) <Michael.H.Kelley@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Jack
> Morgenstein <jackm@mellanox.com>; stable@vger.kernel.org
> Subject: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items
> 
> When we hot-remove the device, we first receive a PCI_EJECT message and
> then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0.
> 
> The first message is offloaded to hv_eject_device_work(), and the second
> is offloaded to pci_devices_present_work(). Both the paths can be running
> list_del(&hpdev->list_entry), causing general protection fault, because
> system_wq can run them concurrently.
> 
> The patch eliminates the race condition.
> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Tested-by: Adrian Suhov <v-adsuho@microsoft.com>
> Tested-by: Chris Valean <v-chvale@microsoft.com>
> Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
> Cc: Jack Morgenstein <jackm@mellanox.com>
> Cc: stable@vger.kernel.org
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: K. Y. Srinivasan <kys@microsoft.com>
> ---
>  drivers/pci/host/pci-hyperv.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 

Reviewed-by: Michael Kelley <mikelley@microsoft.com>