• Oliver O'Halloran's avatar
    powerpc/eeh: Fix race when freeing PDNs · 5ef753ae
    Oliver O'Halloran authored
    When hot-adding devices we rely on the hotplug driver to create pci_dn's
    for the devices under the hotplug slot. Converse, when hot-removing the
    driver will remove the pci_dn's that it created. This is a problem because
    the pci_dev is still live until it's refcount drops to zero. This can
    happen if the driver is slow to tear down it's internal state. Ideally, the
    driver would not attempt to perform any config accesses to the device once
    it's been marked as removed, but sometimes it happens. As a result, we
    might attempt to access the pci_dn for a device that has been torn down and
    the kernel may crash as a result.
    
    To fix this, don't free the pci_dn unless the corresponding pci_dev has
    been released.  If the pci_dev is still live, then we mark the pci_dn with
    a flag that indicates the pci_dev's release function should free it.
    Signed-off-by: default avatarOliver O'Halloran <oohall@gmail.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/20190903101605.2890-3-oohall@gmail.com
    5ef753ae
pci-bridge.h 9.17 KB