From 05ba75f848647135f063199dc0e9f40fee769724 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Tue, 9 Feb 2016 15:50:21 +1100 Subject: 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 Reported-by: Pradipta Ghosh Signed-off-by: Gavin Shan Tested-by: Andrew Donnellan Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/powernv/eeh-powernv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/platforms/powernv/eeh-powernv.c') diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c index 5f152b95ca0c..87f47e55aab6 100644 --- a/arch/powerpc/platforms/powernv/eeh-powernv.c +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c @@ -444,9 +444,12 @@ 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 -- cgit v1.2.3