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

[Haiyang Zhang]

> -Original Message-
> From: Dexuan Cui
> Sent: Tuesday, March 6, 2018 1:22 PM
> To: bhelg...@google.com; linux-...@vger.kernel.org; KY Srinivasan
> ; Stephen Hemminger ;
> o...@aepfle.de; a...@canonical.com; jasow...@redhat.com
> Cc: linux-ker...@vger.kernel.org; driverdev-devel@linuxdriverproject.org;
> Haiyang Zhang ; vkuzn...@redhat.com;
> marcelo.ce...@canonical.com; Michael Kelley (EOSG)
> ; Dexuan Cui ; Jack
> Morgenstein ; sta...@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(>list_entry), causing general protection fault, because
> system_wq can run them concurrently.
> 
> The patch eliminates the race condition.
> 
> Signed-off-by: Dexuan Cui 
> Tested-by: Adrian Suhov 
> Tested-by: Chris Valean 
> Cc: Vitaly Kuznetsov 
> Cc: Jack Morgenstein 
> Cc: sta...@vger.kernel.org
> Cc: Stephen Hemminger 
> Cc: K. Y. Srinivasan 
> ---

Acked-by: Haiyang Zhang 
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RE: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items

[Michael Kelley (EOSG)]

> -Original Message-
> From: Dexuan Cui
> Sent: Tuesday, March 6, 2018 10:22 AM
> To: bhelg...@google.com; linux-...@vger.kernel.org; KY Srinivasan 
> ;
> Stephen Hemminger ; o...@aepfle.de; 
> a...@canonical.com;
> jasow...@redhat.com
> Cc: linux-ker...@vger.kernel.org; driverdev-devel@linuxdriverproject.org; 
> Haiyang Zhang
> ; vkuzn...@redhat.com; marcelo.ce...@canonical.com; 
> Michael
> Kelley (EOSG) ; Dexuan Cui 
> ; Jack
> Morgenstein ; sta...@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(>list_entry), causing general protection fault, because
> system_wq can run them concurrently.
> 
> The patch eliminates the race condition.
> 
> Signed-off-by: Dexuan Cui 
> Tested-by: Adrian Suhov 
> Tested-by: Chris Valean 
> Cc: Vitaly Kuznetsov 
> Cc: Jack Morgenstein 
> Cc: sta...@vger.kernel.org
> Cc: Stephen Hemminger 
> Cc: K. Y. Srinivasan 
> ---
>  drivers/pci/host/pci-hyperv.c | 17 ++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 

Reviewed-by: Michael Kelley 
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