"BUG: using smp_processor_id() in preemptible" with KPTI on 4.14.11

[Thomas Zeitlhofer]

Hello,

on an Ivybridge CPU, I get with 4.14.11:

   BUG: using smp_processor_id() in preemptible [00000000] code: ovsdb-server/4510
   caller is native_flush_tlb_single+0x57/0xc0
   CPU: 3 PID: 4510 Comm: ovsdb-server Not tainted 4.14.11-kvm-00434-gcd0b8eb84f5c #3
   Hardware name: MSI MS-7798/B75MA-P45 (MS-7798), BIOS V1.9 09/30/2013
   Call Trace:
    dump_stack+0x5c/0x86
    check_preemption_disabled+0xdd/0xe0
    native_flush_tlb_single+0x57/0xc0
    ? __set_pte_vaddr+0x2d/0x40
    __set_pte_vaddr+0x2d/0x40
    set_pte_vaddr+0x2f/0x40
    cea_set_pte+0x30/0x40
    ds_update_cea.constprop.4+0x4d/0x70
    reserve_ds_buffers+0x159/0x410
    ? wp_page_copy+0x36d/0x6a0
    x86_reserve_hardware+0x150/0x160
    x86_pmu_event_init+0x3e/0x1f0
    perf_try_init_event+0x69/0x80
    perf_event_alloc+0x652/0x740
    SyS_perf_event_open+0x3f6/0xd60
    do_syscall_64+0x5c/0x190
    entry_SYSCALL64_slow_path+0x25/0x25
   RIP: 0033:0x74a1d94580b9
   RSP: 002b:00007fff0c01d5d8 EFLAGS: 00000206 ORIG_RAX: 000000000000012a
   RAX: ffffffffffffffda RBX: 00007fff0c01d7b0 RCX: 000074a1d94580b9
   RDX: 00000000ffffffff RSI: 0000000000000000 RDI: 00007fff0c01d5e0
   RBP: 0000000000000000 R08: 0000000000000000 R09: 0000007000000000
   R10: 00000000ffffffff R11: 0000000000000206 R12: 0000000000000008
   R13: 0000000000000000 R14: 00007fff0c01d790 R15: 00005df43a799600

This does not show up when booting with pti=off.

Maybe it is related to the issue that is fixed for the upcoming 4.4.110
release by https://lkml.org/lkml/2018/1/3/692

Thanks,

Thomas