4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Prarit Bhargava <[email protected]>


[ Upstream commit 6d6daa20945f3f598e56e18d1f926c08754f5801 ]

hswep_uncore_cpu_init() uses a hardcoded physical package id 0 for the boot
cpu. This works as long as the boot CPU is actually on the physical package
0, which is normaly the case after power on / reboot.

But it fails with a NULL pointer dereference when a kdump kernel is started
on a secondary socket which has a different physical package id because the
locigal package translation for physical package 0 does not exist.

Use the logical package id of the boot cpu instead of hard coded 0.

[ tglx: Rewrote changelog once more ]

Fixes: cf6d445f6897 ("perf/x86/uncore: Track packages, not per CPU data")
Signed-off-by: Prarit Bhargava <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Harish Chegondi <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Cc: [email protected]
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 arch/x86/events/intel/uncore_snbep.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -2686,7 +2686,7 @@ static struct intel_uncore_type *hswep_m
 
 void hswep_uncore_cpu_init(void)
 {
-       int pkg = topology_phys_to_logical_pkg(0);
+       int pkg = boot_cpu_data.logical_proc_id;
 
        if (hswep_uncore_cbox.num_boxes > boot_cpu_data.x86_max_cores)
                hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;


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