• Dexuan Cui's avatar
    PCI: hv: Fix a memory leak in hv_eject_device_work() · 05f151a7
    Dexuan Cui authored
    When a device is created in new_pcichild_device(), hpdev->refs is set
    to 2 (i.e. the initial value of 1 plus the get_pcichild()).
    
    When we hot remove the device from the host, in a Linux VM we first call
    hv_pci_eject_device(), which increases hpdev->refs by get_pcichild() and
    then schedules a work of hv_eject_device_work(), so hpdev->refs becomes
    3 (let's ignore the paired get/put_pcichild() in other places). But in
    hv_eject_device_work(), currently we only call put_pcichild() twice,
    meaning the 'hpdev' struct can't be freed in put_pcichild().
    
    Add one put_pcichild() to fix the memory leak.
    
    The device can also be removed when we run "rmmod pci-hyperv". On this
    path (hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_devices_present()),
    hpdev->refs is 2, and we do correctly call put_pcichild() twice in
    pci_devices_present_work().
    
    Fixes: 4daace0d ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs")
    Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
    [lorenzo.pieralisi@arm.com: commit log rework]
    Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Reviewed-by: default avatarStephen Hemminger <stephen@networkplumber.org>
    Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
    Cc: stable@vger.kernel.org
    05f151a7
pci-hyperv.c 74.1 KB