@@ -81,6 +81,7 @@ struct pci_dn;
#define EEH_PE_KEEP (1 << 8) /* Keep PE on hotplug */
#define EEH_PE_CFG_RESTRICTED (1 << 9) /* Block config on error */
#define EEH_PE_REMOVED (1 << 10) /* Removed permanently */
+#define EEH_PE_PRI_BUS (1 << 11) /* Cached primary bus */
struct eeh_pe {
int type; /* PE type: PHB/Bus/Device */
@@ -561,6 +561,7 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
*/
eeh_pe_state_mark(pe, EEH_PE_KEEP);
if (bus) {
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
pci_lock_rescan_remove();
pcibios_remove_pci_devices(bus);
pci_unlock_rescan_remove();
@@ -792,6 +793,7 @@ perm_error:
* the their PCI config any more.
*/
if (frozen_bus) {
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
pci_lock_rescan_remove();
@@ -875,6 +877,7 @@ static void eeh_handle_special_event(void)
continue;
/* Notify all devices to be down */
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
bus = eeh_pe_bus_get(phb_pe);
eeh_pe_dev_traverse(pe,
eeh_report_failure, NULL);
@@ -906,7 +906,7 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
bus = pe->phb->bus;
} else if (pe->type & EEH_PE_BUS ||
pe->type & EEH_PE_DEVICE) {
- if (pe->bus) {
+ if (pe->state & EEH_PE_PRI_BUS) {
bus = pe->bus;
goto out;
}
@@ -457,9 +457,12 @@ static void *pnv_eeh_probe(struct pci_dn *pdn, void *data)
* PCI devices of the PE are expected to be removed prior
* to PE reset.
*/
- if (!edev->pe->bus)
+ if (!(edev->pe->state & EEH_PE_PRI_BUS)) {
edev->pe->bus = pci_find_bus(hose->global_number,
pdn->busno);
+ if (edev->pe->bus)
+ edev->pe->state |= EEH_PE_PRI_BUS;
+ }
/*
* Enable EEH explicitly so that we will do EEH check
This is a note to let you know that I have just added a patch titled powerpc/eeh: Fix stale cached primary bus to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From fe260c24c5d2ff184d5f759d4ac67a3c080a8c46 Mon Sep 17 00:00:00 2001 From: Gavin Shan <gwshan@linux.vnet.ibm.com> Date: Tue, 9 Feb 2016 15:50:21 +1100 Subject: powerpc/eeh: Fix stale cached primary bus commit 05ba75f848647135f063199dc0e9f40fee769724 upstream. When PE is created, its primary bus is cached to pe->bus. At later point, the cached primary bus is returned from eeh_pe_bus_get(). However, we could get stale cached primary bus and run into kernel crash in one case: full hotplug as part of fenced PHB error recovery releases all PCI busses under the PHB at unplugging time and recreate them at plugging time. pe->bus is still dereferencing the PCI bus that was released. This adds another PE flag (EEH_PE_PRI_BUS) to represent the validity of pe->bus. pe->bus is updated when its first child EEH device is online and the flag is set. Before unplugging in full hotplug for error recovery, the flag is cleared. Fixes: 8cdb2833 ("powerpc/eeh: Trace PCI bus from PE") Reported-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Reported-by: Pradipta Ghosh <pradghos@in.ibm.com> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/powerpc/include/asm/eeh.h | 1 + arch/powerpc/kernel/eeh_driver.c | 3 +++ arch/powerpc/kernel/eeh_pe.c | 2 +- arch/powerpc/platforms/powernv/eeh-powernv.c | 5 ++++- 4 files changed, 9 insertions(+), 2 deletions(-) -- 2.7.0