From: Dexuan Cui <de...@microsoft.com> Sent: Friday, June 21, 2019 4:45 PM
>
> The commit 05f151a73ec2 itself is correct, but it exposes this
> use-after-free bug, which is caught by some memory debug options.
>
> Add a Fixes tag to indicate the dependency.
>
> Fixes: 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")
> Signed-off-by: Dexuan Cui <de...@microsoft.com>
> Cc: sta...@vger.kernel.org
> ---
>
> In v2:
> Replaced "hpdev->hbus" with "hbus", since we have the new "hbus" variable.
> [Michael
> Kelley]
>
> drivers/pci/controller/pci-hyperv.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-hyperv.c
> b/drivers/pci/controller/pci-hyperv.c
> index 808a182830e5..5dadc964ad3b 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -1880,6 +1880,7 @@ static void hv_pci_devices_present(struct
> hv_pcibus_device
> *hbus,
> static void hv_eject_device_work(struct work_struct *work)
> {
> struct pci_eject_response *ejct_pkt;
> + struct hv_pcibus_device *hbus;
> struct hv_pci_dev *hpdev;
> struct pci_dev *pdev;
> unsigned long flags;
> @@ -1890,6 +1891,7 @@ static void hv_eject_device_work(struct work_struct
> *work)
> } ctxt;
>
> hpdev = container_of(work, struct hv_pci_dev, wrk);
> + hbus = hpdev->hbus;
>
> WARN_ON(hpdev->state != hv_pcichild_ejecting);
>
> @@ -1900,8 +1902,7 @@ static void hv_eject_device_work(struct work_struct
> *work)
> * because hbus->pci_bus may not exist yet.
> */
> wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
> - pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0,
> - wslot);
> + pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
> if (pdev) {
> pci_lock_rescan_remove();
> pci_stop_and_remove_bus_device(pdev);
> @@ -1909,9 +1910,9 @@ static void hv_eject_device_work(struct work_struct
> *work)
> pci_unlock_rescan_remove();
> }
>
> - spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
> + spin_lock_irqsave(&hbus->device_list_lock, flags);
> list_del(&hpdev->list_entry);
> - spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
> + spin_unlock_irqrestore(&hbus->device_list_lock, flags);
>
> if (hpdev->pci_slot)
> pci_destroy_slot(hpdev->pci_slot);
> @@ -1920,7 +1921,7 @@ static void hv_eject_device_work(struct work_struct
> *work)
> ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
> ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
> ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
> - vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
> + vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
> sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
> VM_PKT_DATA_INBAND, 0);
>
> @@ -1929,7 +1930,9 @@ static void hv_eject_device_work(struct work_struct
> *work)
> /* For the two refs got in new_pcichild_device() */
> put_pcichild(hpdev);
> put_pcichild(hpdev);
> - put_hvpcibus(hpdev->hbus);
> + /* hpdev has been freed. Do not use it any more. */
> +
> + put_hvpcibus(hbus);
> }
>
> /**
> --
> 2.17.1
Reviewed-by: Michael Kelley <mikel...@microsoft.com>
