From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
commit a3aa256b7258b3d19f8b44557cc64525a993b941 upstream.
Backport required because pci_hp_add_devices() was called
pcibios_add_pci_devices() in 4.6 - mpe.
The PE primary bus cannot be got from its child devices when having
full hotplug in error recovery. The PE primary bus is cached, which
is done in commit <05ba75f84864> ("powerpc/eeh: Fix stale cached primary
bus"). In eeh_reset_device(), the flag (EEH_PE_PRI_BUS) is cleared
before the PCI hot remove. eeh_pe_bus_get() then returns NULL as the
PE primary bus in pnv_eeh_reset() and it crashes the kernel eventually.
This fixes the issue by clearing the flag (EEH_PE_PRI_BUS) before the
PCI hot add. With it, the PowerNV EEH reset backend (pnv_eeh_reset())
can get valid PE primary bus through eeh_pe_bus_get().
Fixes: 67086e32b564 ("powerpc/eeh: powerpc/eeh: Support error recovery for VF PE")
Reported-by: Pridhiviraj Paidipeddi <ppaiddipe@xxxxxxxxxx>
Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
---
arch/powerpc/kernel/eeh_driver.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 1aa7abaf0961..4a27a9684442 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -648,7 +648,6 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
if (pe->type & EEH_PE_VF) {
eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
} else {
- eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
pci_lock_rescan_remove();
pcibios_remove_pci_devices(bus);
pci_unlock_rescan_remove();
@@ -698,10 +697,12 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
*/
edev = list_first_entry(&pe->edevs, struct eeh_dev, list);
eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
- if (pe->type & EEH_PE_VF)
+ if (pe->type & EEH_PE_VF) {
eeh_add_virt_device(edev, NULL);
- else
+ } else {
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
pcibios_add_pci_devices(bus);
+ }
} else if (frozen_bus && rmv_data->removed) {
pr_info("EEH: Sleep 5s ahead of partial hotplug\n");
ssleep(5);
--
2.7.4
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