On 01/18/2017 05:45 AM, Greg Kroah-Hartman wrote: > 4.9-stable review patch. If anyone has any objections, please let me know. > Nack. The value of boot_cpu_data.logical_proc_id may be uninitialized and set to default -1 on systems that pick a random core as boot cpu. This was inadvertently fixed by 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust") which is in 4.10-rc1. Before 9d85eb9119f4: [ 3.971539] hswep_uncore_cpu_init: cpu 5 pkg 0 boot_cpu_data.logical_proc_id 65535 [ 3.976504] hswep_uncore_cpu_init: cpu 5 pkg 0 cpu_data(0).logical_proc_id 0 After 9d85eb9119f4: [ 3.919112] hswep_uncore_cpu_init: cpu 5 pkg 0 boot_cpu_data.logical_proc_id 0 [ 3.923391] hswep_uncore_cpu_init: cpu 5 pkg 0 cpu_data(0).logical_proc_id 0 This patch should not be applied to any stable branch. P. > ------------------ > > From: Prarit Bhargava <prarit@xxxxxxxxxx> > > commit 6d6daa20945f3f598e56e18d1f926c08754f5801 upstream. > > 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@xxxxxxxxxx> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxx> > Cc: H. Peter Anvin <hpa@xxxxxxxxx> > Cc: Harish Chegondi <harish.chegondi@xxxxxxxxx> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx> > Cc: Kan Liang <kan.liang@xxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Stephane Eranian <eranian@xxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Vince Weaver <vincent.weaver@xxxxxxxxx> > Link: http://lkml.kernel.org/r/1483628965-2890-1-git-send-email-prarit@xxxxxxxxxx > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > 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; > > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html