[PATCH] perf/x86/intel/uncore: Avoid null dereferences (uncore_extra_pci_dev)

[Steve Wahl]

If an uncore has no pci_init routine, or that routine fails,
uncore_pci_init is not called, and memory is not allocated for
uncore_extra_pci_dev.

So check to make sure uncore_extra_pci_dev is not NULL before use.

And fix the case that led us to discover the null derefs; don't fail
snbep_pci2phy_map_init if BIOS doesn't supply pcibus_to_node
information.

Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci bus die id 
from NUMA info")

Signed-off-by: Steve Wahl <steve.w...@hpe.com>
---
 arch/x86/events/intel/uncore_snbep.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c 
b/arch/x86/events/intel/uncore_snbep.c
index b79951d0707c..14c24356a2fa 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -1373,11 +1373,11 @@ static int snbep_pci2phy_map_init(int devid, int 
nodeid_loc, int idmap_loc, bool
                /*
                 * The nodeid and idmap registers only contain enough
                 * information to handle 8 nodes.  On systems with more
-                * than 8 nodes, we need to rely on NUMA information,
+                * than 8 nodes, if available we rely on NUMA information,
                 * filled in from BIOS supplied information, to determine
                 * the topology.
                 */
-               if (nr_node_ids <= 8) {
+               if ((nr_node_ids <= 8) || (pcibus_to_node(ubox_dev->bus) == 
-1)) {
                        /* get the Node ID of the local register */
                        err = pci_read_config_dword(ubox_dev, nodeid_loc, 
&config);
                        if (err)
@@ -2865,7 +2865,9 @@ void hswep_uncore_cpu_init(void)
                hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
 
        /* Detect 6-8 core systems with only two SBOXes */
-       if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
+       if (!uncore_extra_pci_dev)
+               hswep_uncore_sbox.num_boxes = 2;
+       else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
                u32 capid4;
 
                
pci_read_config_dword(uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
@@ -3243,6 +3245,8 @@ void bdx_uncore_cpu_init(void)
        if (boot_cpu_data.x86_model == 86) {
                uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
        /* Detect systems with no SBOXes */
+       } else if (!uncore_extra_pci_dev) {
+               bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
        } else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
                struct pci_dev *pdev;
                u32 capid4;
-- 
2.26.2