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Peter Zijlstra 75f80859b1 perf/x86/intel/pebs: Robustify PEBS buffer drain 
Vince Weaver and Stephane Eranian reported warnings in the PEBS
code when running the perf fuzzer. Stephane wrote:

  > I can reproduce the problem on my HSW running the fuzzer.
  >
  > I can see why this could be happening if you are mixing PEBS and non PEBS events
  > in the bottom 4 counters. I suspect:
  >         for (bit = 0; bit < x86_pmu.max_pebs_events; bit++) {
  >                 if ((counts[bit] == 0) && (error[bit] == 0))
  >                         continue;
  >
  > This test is not correct when you have non-PEBS events mixed with
  > PEBS events and they overflow at the same time. They will have
  > counts[i] != 0 but error[i] == 0, and thus you fall thru the loop
  > and hit the assert. Or it is something along those lines.

The only way I can make this work is if ->status only has !PEBS events
set, because if it has both set we'll take that slow path which masks
out the !PEBS bits.

After masking there are 3 options:

 - there is one bit set, and its @bit, we increment counts[bit].

 - there are multiple bits set, we increment error[] for each set bit,
   we do not increment counts[].

 - there are no bits set, we do nothing.

The intent was to never increment counts[] for !PEBS events.

Now if we start out with only a single !PEBS event set, we'll pass the
test and increment counts[] for a !PEBS and hit the warn.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 		2015-08-04 10:17:01 +02:00
..
acpi Power management and ACPI material for v4.2-rc1 2015-06-23 14:18:07 -07:00
apic x86/irq: Plug irq vector hotplug race 2015-07-07 11:54:04 +02:00
cpu perf/x86/intel/pebs: Robustify PEBS buffer drain 2015-08-04 10:17:01 +02:00
fpu x86/fpu: Disable dependent CPU features on "noxsave" 2015-07-21 08:20:42 +02:00
kprobes Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 14:37:47 -07:00
.gitignore
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Makefile Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
alternative.c Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
amd_gart_64.c x86: enable DMA CMA with swiotlb 2014-06-04 16:53:57 -07:00
amd_nb.c x86/gart: Check for GART support before accessing GART registers 2015-05-06 11:15:53 +02:00
apb_timer.c x86/intel-mid: Delay initialization of APB timer 2015-04-24 15:36:51 +02:00
aperture_64.c x86/gart: Check for GART support before accessing GART registers 2015-05-06 11:15:53 +02:00
apm_32.c cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic 2014-11-12 21:17:27 +01:00
asm-offsets.c x86: Merge common 32-bit values in asm-offsets.c 2015-05-05 20:48:02 +02:00
asm-offsets_32.c x86: Remove unused TI_cpu 2015-05-05 20:48:02 +02:00
asm-offsets_64.c x86/asm/entry: (Re-)rename __NR_entry_INT80_compat_max to __NR_syscall_compat_max 2015-06-08 23:43:38 +02:00
audit_64.c x86: hook up execveat system call 2014-12-13 12:42:51 -08:00
bootflag.c x86: don't use module_init for non-modular core bootflag code 2015-06-16 14:12:34 -04:00
check.c mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute 2015-06-24 17:49:44 -07:00
cpuid.c x86, cpuid: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:51 -07:00
crash.c x86/mm: Decouple <linux/vmalloc.h> from <asm/io.h> 2015-06-03 12:02:00 +02:00
crash_dump_32.c
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crash_dump_64.c
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devicetree.c Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
doublefault.c
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dumpstack.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 13:23:34 -07:00
dumpstack_32.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 13:23:34 -07:00
dumpstack_64.c x86/kernel: Use kstack_end() in dumpstack_64.c 2015-02-23 18:37:13 +01:00
e820.c The libnvdimm sub-system introduces, in addition to the libnvdimm-core, 2015-06-29 10:34:42 -07:00
early-quirks.c Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2015-06-26 13:18:51 -07:00
early_printk.c x86/earlyprintk: Allow early_printk() to use console style parameters like '115200n8' 2015-07-06 17:33:47 +02:00
espfix_64.c x86/espfix: Init espfix on the boot CPU side 2015-07-06 15:00:34 +02:00
ftrace.c module: remove mod arg from module_free, rename module_memfree(). 2015-01-20 11:38:33 +10:30
head.c
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head32.c x86: Store a per-cpu shadow copy of CR4 2015-02-04 12:10:42 +01:00
head64.c x86/kasan: Fix KASAN shadow region page tables 2015-07-06 14:53:13 +02:00
head_32.S Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
head_64.S x86/kasan: Fix KASAN shadow region page tables 2015-07-06 14:53:13 +02:00
hpet.c x86/hpet: Use proper hpet device number for MSI allocation 2015-06-21 16:38:40 +02:00
hw_breakpoint.c perf/x86/hw_breakpoints: Fix check for kernel-space breakpoints 2015-08-04 10:16:55 +02:00
i386_ksyms_32.c preempt: Use preempt_schedule_context() as the official tracing preemption point 2015-06-07 15:57:42 +02:00
i8237.c
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i8253.c
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i8259.c x86/asm/entry/irq: Clean up IRQn_VECTOR macros 2015-05-10 12:34:28 +02:00
io_delay.c
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ioport.c x86/asm/entry: Rename 'init_tss' to 'cpu_tss' 2015-03-06 08:32:58 +01:00
iosf_mbi.c x86/platform/intel/iosf: Add debugfs config option for IOSF 2014-09-19 13:08:43 +02:00
irq.c x86/irq: Retrieve irq data after locking irq_desc 2015-07-07 11:54:04 +02:00
irq_32.c x86/irq: Merge irq_regs & irq_stat 2015-05-10 12:34:27 +02:00
irq_64.c x86/irq: Merge irq_regs & irq_stat 2015-05-10 12:34:27 +02:00
irq_work.c x86: Consolidate irq entering inlines 2015-05-15 16:04:49 +02:00
irqinit.c Merge branch 'x86/ras' into x86/core, to fix conflicts 2015-06-07 15:35:27 +02:00
jump_label.c
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kdebugfs.c
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kexec-bzimage64.c x86/kexec: prepend elfcorehdr instead of appending it to the crash-kernel command-line. 2015-06-30 19:44:57 -07:00
kgdb.c Linux 4.0-rc7 2015-04-08 09:01:54 +02:00
ksysfs.c
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kvm.c The bulk of the changes here is for x86. And for once it's not 2015-06-24 09:36:49 -07:00
kvmclock.c x86: kvmclock: set scheduler clock stable 2015-05-29 14:01:52 +02:00
ldt.c Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option" 2014-05-21 10:22:59 -07:00
livepatch.c livepatch: kernel: add support for live patching 2014-12-22 15:40:49 +01:00
machine_kexec_32.c x86, irq: Move IOAPIC related declarations from hw_irq.h into io_apic.h 2014-12-16 14:08:17 +01:00
machine_kexec_64.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2015-06-23 14:07:26 -07:00
mcount_64.S ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter 2014-12-01 14:08:58 -05:00
mmconf-fam10h_64.c
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module.c x86/mm/KASLR: Propagate KASLR status to kernel proper 2015-04-03 15:26:15 +02:00
mpparse.c x86: Cleanup irq_domain ops 2015-04-24 15:36:55 +02:00
msr.c x86, msr: Use seek definitions instead of hard-coded values 2014-10-17 13:40:55 -07:00
nmi.c x86/nmi/64: Improve nested NMI comments 2015-07-17 12:50:11 +02:00
nmi_selftest.c
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paravirt-spinlocks.c locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS 2015-05-11 09:52:09 +02:00
paravirt.c Merge branch 'linus' into x86/asm, before applying dependent patch 2015-05-08 13:33:33 +02:00
paravirt_patch_32.c locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching 2015-05-08 12:37:09 +02:00
paravirt_patch_64.c Merge branch 'locking/core' into x86/core, to prepare for dependent patch 2015-06-03 10:07:35 +02:00
pci-calgary_64.c x86, calgary: Use 8M TCE table size by default 2014-04-10 19:51:32 -07:00
pci-dma.c x86: Deinline dma_free_attrs() 2015-05-05 20:48:02 +02:00
pci-iommu_table.c
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pci-nommu.c
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pci-swiotlb.c x86/swiotlb: Try coherent allocations with __GFP_NOWARN 2015-06-11 08:28:38 +02:00
pcspeaker.c
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perf_regs.c perf/x86/64: Report regs_user->ax too in get_regs_user() 2015-04-11 13:08:53 +02:00
pmc_atom.c x86: pmc_atom: Expose contents of PSS 2015-01-20 12:50:14 +01:00
pmem.c libnvdimm: Set numa_node to NVDIMM devices 2015-06-26 11:23:38 -04:00
probe_roms.c
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process.c x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 2015-07-18 03:42:51 +02:00
process_32.c x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit 2015-06-30 19:45:01 -07:00
process_64.c x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit 2015-06-30 19:45:01 -07:00
ptrace.c x86/fpu: Factor out fpu/regset.h from fpu/internal.h 2015-05-19 15:48:06 +02:00
pvclock.c x86: pvclock: Really remove the sched notifier for cross-cpu migrations 2015-04-27 15:49:30 +02:00
quirks.c x86: HPET force enable for e6xx based systems 2014-09-15 17:53:35 -07:00
reboot.c x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk 2015-04-01 14:08:09 +02:00
reboot_fixups_32.c
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relocate_kernel_32.S x86/asm: Optimize unnecessarily wide TEST instructions 2015-03-07 11:12:43 +01:00
relocate_kernel_64.S x86/asm: Replace "MOVQ $imm, %reg" with MOVL 2015-04-01 13:17:39 +02:00
resource.c x86: don't exclude low BIOS area when allocating address space for non-PCI cards 2014-07-16 12:29:36 -06:00
rtc.c kernel.h: remove ancient __FUNCTION__ hack 2015-02-12 18:54:13 -08:00
setup.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-04 08:58:50 -07:00
setup_percpu.c x86: Convert a few more per-CPU items to read-mostly ones 2014-11-04 20:13:28 +01:00
signal.c x86/fpu: Split out fpu/signal.h from fpu/internal.h for signal frame handling functions 2015-05-19 15:48:05 +02:00
smp.c x86: Consolidate irq entering inlines 2015-05-15 16:04:49 +02:00
smpboot.c genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now 2015-07-15 10:39:17 +02:00
stacktrace.c
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step.c
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sys_x86_64.c x86/mm: Improve AMD Bulldozer ASLR workaround 2015-03-31 10:01:17 +02:00
sysfb.c x86/sysfb: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:52 -07:00
sysfb_efi.c
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sysfb_simplefb.c x86/simplefb: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:52 -07:00
tboot.c
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tce_64.c
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test_nx.c
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test_rodata.c treewide: Fix typo in printk messages 2015-03-06 23:05:39 +01:00
time.c x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
tls.c x86, tls: Interpret an all-zero struct user_desc as "no segment" 2015-01-22 21:45:07 +01:00
tls.h
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topology.c
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trace_clock.c
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tracepoint.c
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traps.c Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
tsc.c perf/x86: Add a native_perf_sched_clock_from_tsc() 2015-08-04 10:16:55 +02:00
tsc_msr.c
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tsc_sync.c x86: Replace cpu_**_mask() with topology_**_cpumask() 2015-05-27 15:22:17 +02:00
uprobes.c uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more clever 2015-07-31 10:38:06 +02:00
verify_cpu.S
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vm86_32.c x86/asm/entry: Rename 'init_tss' to 'cpu_tss' 2015-03-06 08:32:58 +01:00
vmlinux.lds.S x86-64: Use RIP-relative addressing for most per-CPU accesses 2014-11-04 20:43:14 +01:00
vsmp_64.c x86: replace __init_or_module with __init in non-modular vsmp_64.c 2015-06-16 14:12:41 -04:00
x86_init.c PCI changes for the v4.2 merge window: 2015-06-23 13:41:24 -07:00
x8664_ksyms_64.c preempt: Use preempt_schedule_context() as the official tracing preemption point 2015-06-07 15:57:42 +02:00