linux/arch
Kan Liang c3d266c8a9 perf/x86/intel: Fix PEBS warning by only restoring active PMU in pmi
This patch tries to fix a PEBS warning found in my stress test. The
following perf command can easily trigger the pebs warning or spurious
NMI error on Skylake/Broadwell/Haswell platforms:

  sudo perf record -e 'cpu/umask=0x04,event=0xc4/pp,cycles,branches,ref-cycles,cache-misses,cache-references' --call-graph fp -b -c1000 -a

Also the NMI watchdog must be enabled.

For this case, the events number is larger than counter number. So
perf has to do multiplexing.

In perf_mux_hrtimer_handler, it does perf_pmu_disable(), schedule out
old events, rotate_ctx, schedule in new events and finally
perf_pmu_enable().

If the old events include precise event, the MSR_IA32_PEBS_ENABLE
should be cleared when perf_pmu_disable().  The MSR_IA32_PEBS_ENABLE
should keep 0 until the perf_pmu_enable() is called and the new event is
precise event.

However, there is a corner case which could restore PEBS_ENABLE to
stale value during the above period. In perf_pmu_disable(), GLOBAL_CTRL
will be set to 0 to stop overflow and followed PMI. But there may be
pending PMI from an earlier overflow, which cannot be stopped. So even
GLOBAL_CTRL is cleared, the kernel still be possible to get PMI. At
the end of the PMI handler, __intel_pmu_enable_all() will be called,
which will restore the stale values if old events haven't scheduled
out.

Once the stale pebs value is set, it's impossible to be corrected if
the new events are non-precise. Because the pebs_enabled will be set
to 0. x86_pmu.enable_all() will ignore the MSR_IA32_PEBS_ENABLE
setting. As a result, the following NMI with stale PEBS_ENABLE
trigger pebs warning.

The pending PMI after enabled=0 will become harmless if the NMI handler
does not change the state. This patch checks cpuc->enabled in pmi and
only restore the state when PMU is active.

Here is the dump:

  Call Trace:
   <NMI>  [<ffffffff813c3a2e>] dump_stack+0x63/0x85
   [<ffffffff810a46f2>] warn_slowpath_common+0x82/0xc0
   [<ffffffff810a483a>] warn_slowpath_null+0x1a/0x20
   [<ffffffff8100fe2e>] intel_pmu_drain_pebs_nhm+0x2be/0x320
   [<ffffffff8100caa9>] intel_pmu_handle_irq+0x279/0x460
   [<ffffffff810639b6>] ? native_write_msr_safe+0x6/0x40
   [<ffffffff811f290d>] ? vunmap_page_range+0x20d/0x330
   [<ffffffff811f2f11>] ?  unmap_kernel_range_noflush+0x11/0x20
   [<ffffffff8148379f>] ? ghes_copy_tofrom_phys+0x10f/0x2a0
   [<ffffffff814839c8>] ? ghes_read_estatus+0x98/0x170
   [<ffffffff81005a7d>] perf_event_nmi_handler+0x2d/0x50
   [<ffffffff810310b9>] nmi_handle+0x69/0x120
   [<ffffffff810316f6>] default_do_nmi+0xe6/0x100
   [<ffffffff810317f2>] do_nmi+0xe2/0x130
   [<ffffffff817aea71>] end_repeat_nmi+0x1a/0x1e
   [<ffffffff810639b6>] ? native_write_msr_safe+0x6/0x40
   [<ffffffff810639b6>] ? native_write_msr_safe+0x6/0x40
   [<ffffffff810639b6>] ? native_write_msr_safe+0x6/0x40
   <<EOE>>  <IRQ>  [<ffffffff81006df8>] ?  x86_perf_event_set_period+0xd8/0x180
   [<ffffffff81006eec>] x86_pmu_start+0x4c/0x100
   [<ffffffff8100722d>] x86_pmu_enable+0x28d/0x300
   [<ffffffff811994d7>] perf_pmu_enable.part.81+0x7/0x10
   [<ffffffff8119cb70>] perf_mux_hrtimer_handler+0x200/0x280
   [<ffffffff8119c970>] ?  __perf_install_in_context+0xc0/0xc0
   [<ffffffff8110f92d>] __hrtimer_run_queues+0xfd/0x280
   [<ffffffff811100d8>] hrtimer_interrupt+0xa8/0x190
   [<ffffffff81199080>] ?  __perf_read_group_add.part.61+0x1a0/0x1a0
   [<ffffffff81051bd8>] local_apic_timer_interrupt+0x38/0x60
   [<ffffffff817af01d>] smp_apic_timer_interrupt+0x3d/0x50
   [<ffffffff817ad15c>] apic_timer_interrupt+0x8c/0xa0
   <EOI>  [<ffffffff81199080>] ?  __perf_read_group_add.part.61+0x1a0/0x1a0
   [<ffffffff81123de5>] ?  smp_call_function_single+0xd5/0x130
   [<ffffffff81123ddb>] ?  smp_call_function_single+0xcb/0x130
   [<ffffffff81199080>] ?  __perf_read_group_add.part.61+0x1a0/0x1a0
   [<ffffffff8119765a>] event_function_call+0x10a/0x120
   [<ffffffff8119c660>] ? ctx_resched+0x90/0x90
   [<ffffffff811971e0>] ? cpu_clock_event_read+0x30/0x30
   [<ffffffff811976d0>] ? _perf_event_disable+0x60/0x60
   [<ffffffff8119772b>] _perf_event_enable+0x5b/0x70
   [<ffffffff81197388>] perf_event_for_each_child+0x38/0xa0
   [<ffffffff811976d0>] ? _perf_event_disable+0x60/0x60
   [<ffffffff811a0ffd>] perf_ioctl+0x12d/0x3c0
   [<ffffffff8134d855>] ? selinux_file_ioctl+0x95/0x1e0
   [<ffffffff8124a3a1>] do_vfs_ioctl+0xa1/0x5a0
   [<ffffffff81036d29>] ? sched_clock+0x9/0x10
   [<ffffffff8124a919>] SyS_ioctl+0x79/0x90
   [<ffffffff817ac4b2>] entry_SYSCALL_64_fastpath+0x1a/0xa4
  ---[ end trace aef202839fe9a71d ]---
  Uhhuh. NMI received for unknown reason 2d on CPU 2.
  Do you have a strange power saving mode enabled?

Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.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>
Link: http://lkml.kernel.org/r/1457046448-6184-1-git-send-email-kan.liang@intel.com
[ Fixed various typos and other small details. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-08 12:18:32 +01:00
..
alpha dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
arc arc: SMP: CONFIG_ARC_IPI_DBG cleanup 2016-02-24 14:15:39 +05:30
arm Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-02-28 07:45:58 -08:00
arm64 mm: ASLR: use get_random_long() 2016-02-27 10:28:52 -08:00
avr32 dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
blackfin dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
c6x dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
cris Merge branch 'akpm' (patches from Andrew) 2016-01-21 12:32:08 -08:00
frv dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
h8300 Merge branch 'akpm' (patches from Andrew) 2016-01-21 12:32:08 -08:00
hexagon dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
ia64 [IA64] Enable copy_file_range syscall for ia64 2016-01-22 14:20:01 -08:00
m32r m32r: fix build failure due to SMP and MMU 2016-02-05 18:10:40 -08:00
m68k m68k/defconfig: Update defconfigs for v4.5-rc1 2016-02-01 10:35:38 +01:00
metag dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
microblaze dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
mips mm: ASLR: use get_random_long() 2016-02-27 10:28:52 -08:00
mn10300 dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
nios2 dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
openrisc dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
parisc dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
powerpc mm: ASLR: use get_random_long() 2016-02-27 10:28:52 -08:00
s390 s390/fpu: signals vs. floating point control register 2016-02-22 09:29:35 +01:00
score
sh sh: fix smp_store_mb for !SMP 2016-01-26 10:18:29 +02:00
sparc mm: ASLR: use get_random_long() 2016-02-27 10:28:52 -08:00
tile dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
um um: asm/page.h: remove the pte_high member from struct pte_t 2016-02-05 18:10:40 -08:00
unicore32 dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
x86 perf/x86/intel: Fix PEBS warning by only restoring active PMU in pmi 2016-03-08 12:18:32 +01:00
xtensa dma-mapping: remove <asm-generic/dma-coherent.h> 2016-01-20 17:09:18 -08:00
.gitignore
Kconfig dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00