powerpc/sriov: Remove VF eeh_dev state when disabling SR-IOV

When disabling virtual functions on an SR-IOV adapter we currently do not
correctly remove the EEH state for the now-dead virtual functions. When
removing the pci_dn that was created for the VF when SR-IOV was enabled
we free the corresponding eeh_dev without removing it from the child device
list of the eeh_pe that contained it. This can result in crashes due to the
use-after-free.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190821062655.19735-1-oohall@gmail.com

arch/powerpc/kernel/pci_dn.c

@@ -244,9 +244,22 @@ void remove_dev_pci_data(struct pci_dev *pdev)
 				continue;
 
 #ifdef CONFIG_EEH
-			/* Release EEH device for the VF */
+			/*
+			 * Release EEH state for this VF. The PCI core
+			 * has already torn down the pci_dev for this VF, but
+			 * we're responsible to removing the eeh_dev since it
+			 * has the same lifetime as the pci_dn that spawned it.
+			 */
 			edev = pdn_to_eeh_dev(pdn);
 			if (edev) {
+				/*
+				 * We allocate pci_dn's for the totalvfs count,
+				 * but only only the vfs that were activated
+				 * have a configured PE.
+				 */
+				if (edev->pe)
+					eeh_rmv_from_parent_pe(edev);
+
 				pdn->edev = NULL;
 				kfree(edev);
 			}