powerpc/eeh: Fix stale cached primary bus
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")
Cc: stable@vger.kernel.org #v3.11+
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>
diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index c5eb86f..867c39b 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -81,6 +81,7 @@
#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 */