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Date:   Tue, 6 Aug 2019 15:16:11 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Dexuan Cui <decui@microsoft.com>
Cc:     "lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        Michael Kelley <mikelley@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "driverdev-devel@linuxdriverproject.org" 
        <driverdev-devel@linuxdriverproject.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        KY Srinivasan <kys@microsoft.com>,
        "olaf@aepfle.de" <olaf@aepfle.de>,
        "apw@canonical.com" <apw@canonical.com>,
        "jasowang@redhat.com" <jasowang@redhat.com>,
        vkuznets <vkuznets@redhat.com>,
        "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
        "jackm@mellanox.com" <jackm@mellanox.com>
Subject: Re: [PATCH v2] PCI: hv: Fix panic by calling hv_pci_remove_slots()
 earlier
Message-ID: <20190806201611.GT151852@google.com>
References: <PU1P153MB01693F32F6BB02F9655CC84EBFD90@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM>
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Thanks for updating this.  But you didn't update the subject line,
which is really still a little too low-level.  Maybe Lorenzo will fix
this.  Something like this, maybe?

  PCI: hv: Avoid use of hv_pci_dev->pci_slot after freeing it

On Fri, Aug 02, 2019 at 10:50:20PM +0000, Dexuan Cui wrote:
> 
> The slot must be removed before the pci_dev is removed, otherwise a panic
> can happen due to use-after-free.
> 
> Fixes: 15becc2b56c6 ("PCI: hv: Add hv_pci_remove_slots() when we unload the driver")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Cc: stable@vger.kernel.org
> ---
> 
> Changes in v2:
>   Improved the changelog accordign to the discussion with Bjorn Helgaas:
> 	  https://lkml.org/lkml/2019/8/1/1173
> 	  https://lkml.org/lkml/2019/8/2/1559
> 
>  drivers/pci/controller/pci-hyperv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 6b9cc6e60a..68c611d 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -2757,8 +2757,8 @@ static int hv_pci_remove(struct hv_device *hdev)
>  		/* Remove the bus from PCI's point of view. */
>  		pci_lock_rescan_remove();
>  		pci_stop_root_bus(hbus->pci_bus);
> -		pci_remove_root_bus(hbus->pci_bus);
>  		hv_pci_remove_slots(hbus);
> +		pci_remove_root_bus(hbus->pci_bus);
>  		pci_unlock_rescan_remove();
>  		hbus->state = hv_pcibus_removed;
>  	}
> -- 
> 1.8.3.1
>