The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4df591b20b80cb77920953812d894db259d85bd7 Mon Sep 17 00:00:00 2001

From: Dexuan Cui decui@microsoft.com Date: Fri, 21 Jun 2019 23:45:23 +0000 Subject: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

Fix a use-after-free in hv_eject_device_work().

Fixes: 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()") Signed-off-by: Dexuan Cui decui@microsoft.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Michael Kelley mikelley@microsoft.com Cc: stable@vger.kernel.org

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 82acd6155adf..40b625458afa 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1875,6 +1875,7 @@ 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; @@ -1885,6 +1886,7 @@ 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);

@@ -1895,8 +1897,7 @@ 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); @@ -1904,9 +1905,9 @@ 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); @@ -1915,7 +1916,7 @@ 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);

@@ -1924,7 +1925,9 @@ 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); }

/**