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    SubjectRe: [PATCH] perf/x86/intel/uncore: Initialize with correct logical package ID


    On 01/03/2017 02:24 PM, Prarit Bhargava wrote:
    > On multi-socket Intel v3 processor systems (aka Haswell) kdump can fail with:
    >
    > BUG: unable to handle kernel paging request at 00000000006563a1
    > IP: [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0
    > PGD 0 [ 2.313897]
    > Oops: 0000 [#1] SMP
    > Modules linked in:
    > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0 #1
    > Hardware name: NEC Express5800/T120f [N8100-2285Y]/GA-7WESV-NJ, BIOS 5.0.4009 08/01/2016
    > task: ffff88002bdb8000 task.stack: ffffc90000014000
    > RIP: 0010:[<ffffffff8101b582>] [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0
    > RSP: 0000:ffffc90000017db8 EFLAGS: 00010206
    > RAX: 0000000000656369 RBX: 0000000000000000 RCX: 0000000000001e03
    > RDX: ffff88002b224780 RSI: 0000000000000000 RDI: 0000000000000000
    > RBP: ffffc90000017dc8 R08: 000000000001c880 R09: ffffffff813667e1
    > R10: ffff880030c1c880 R11: 0000000000000000 R12: 0000000000000000
    > R13: ffffffff81c1c090 R14: afafafafafafafaf R15: afafafafafafafaf
    > FS: 0000000000000000(0000) GS:ffff880030c00000(0000) knlGS:0000000000000000
    > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    > CR2: 00000000006563a1 CR3: 000000002fc07000 CR4: 00000000001406b0
    > Stack:
    > ffffc90000017dc8 00000000352bd002 ffffc90000017e00 ffffffff81da17f8
    > 0000000000000000 ffffffff81da16f9 00000000000000f0 afafafafafafafaf
    > afafafafafafafaf ffffc90000017e78 ffffffff81002190 ffffc90000017e00
    > Call Trace:
    > [<ffffffff81da17f8>] intel_uncore_init+0xff/0x2e6
    > [<ffffffff81da16f9>] ? uncore_type_init+0x158/0x158
    > [<ffffffff81002190>] do_one_initcall+0x50/0x190
    > [<ffffffff810af27b>] ? parse_args+0x27b/0x460
    > [<ffffffff81d9c357>] kernel_init_freeable+0x1a5/0x249
    > [<ffffffff81d9ba27>] ? set_debug_rodata+0x12/0x12
    > [<ffffffff81702010>] ? rest_init+0x80/0x80
    > [<ffffffff8170201e>] kernel_init+0xe/0x110
    > [<ffffffff8170f715>] ret_from_fork+0x25/0x30
    > Code: 1a d5 00 39 15 cc 1c c0 00 7e 06 89 15 c4 1c c0 00 48 98 48 8b 15 d7 c3 f7 00 48 8d 04 40 48 8d 04 c2 48 8b 40 10 48 85 c0 74 1b <8b> 70 38 48 8b 78 10 48 8d 4d f4 ba 94 00 00 00 e8 b9 db 38 00
    > RIP [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0
    >
    > This is now occuring because 9d85eb9119f4 ("x86/smpboot: Make logical package
    > management more robust") corrected the physical ID to logical ID mapping of the
    > threads. hswep_uncore_cpu_init() is hard coded for physical socket 0 and if
    > the system is kdump'ing on any other socket the logical package value will be
    > incorrect. The code should not use 0 as the physical ID, and should use
    > the boot cpu's physical package ID in this calculation.
    >
    > Signed-off-by: Prarit Bhargava <prarit@redhat.com>
    > Cc: Thomas Gleixner <tglx@linutronix.de>
    > Cc: Ingo Molnar <mingo@redhat.com>
    > Cc: "H. Peter Anvin" <hpa@zytor.com>
    > Cc: x86@kernel.org
    > Cc: Peter Zijlstra <peterz@infradead.org>
    > Cc: Kan Liang <kan.liang@intel.com>
    > Cc: Borislav Petkov <bp@suse.de>
    > Cc: Harish Chegondi <harish.chegondi@intel.com>
    > ---
    > arch/x86/events/intel/uncore_snbep.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
    > index e6832be714bc..b5fbb59fdc64 100644
    > --- a/arch/x86/events/intel/uncore_snbep.c
    > +++ b/arch/x86/events/intel/uncore_snbep.c
    > @@ -2686,7 +2686,7 @@ static int hswep_pcu_hw_config(struct intel_uncore_box *box, struct perf_event *
    >
    > void hswep_uncore_cpu_init(void)
    > {
    > - int pkg = topology_phys_to_logical_pkg(0);
    > + int pkg = topology_phys_to_logical_pkg(boot_cpu_data.phys_proc_id);

    One thing that just occurred to me as I was looking at other code.
    boot_cpu_data has logical_proc_id, so it may be better to use that instead of
    the lookup function.

    I'm not sure of the usage of physical_to_logical_pkg[] and logical_proc_id.
    Unless tglx or someone already knows of a reason not to use logical_proc_id I
    certainly can change the patch.

    P.

    >
    > 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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