[PATCH 4.9 101/172] perf/x86/intel/uncore: Fix hardcoded socket 0 assumption in the Haswell init code

Greg Kroah-Hartman
2017-07-03T13:44:20Z

From: Prarit Bhargava <prarit@redhat.com>

[ 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 <prarit@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1483628965-2890-1-git-send-email-prarit@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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;