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

[Thomas Zeitlhofer]

On Thu, Jan 04, 2018 at 02:59:06AM +0100, Thomas Zeitlhofer wrote:
> 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

JFYI, the very same kernel does not show this issue on a Haswell CPU.

Thanks,

Thomas