2019-05-27 19:12:12

by Liang, Kan

[permalink] [raw]
Subject: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events

From: Kan Liang <[email protected]>

The perf fuzzer caused skylake machine to crash.

[ 9680.085831] Call Trace:
[ 9680.088301] <IRQ>
[ 9680.090363] perf_output_sample_regs+0x43/0xa0
[ 9680.094928] perf_output_sample+0x3aa/0x7a0
[ 9680.099181] perf_event_output_forward+0x53/0x80
[ 9680.103917] __perf_event_overflow+0x52/0xf0
[ 9680.108266] ? perf_trace_run_bpf_submit+0xc0/0xc0
[ 9680.113108] perf_swevent_hrtimer+0xe2/0x150
[ 9680.117475] ? check_preempt_wakeup+0x181/0x230
[ 9680.122091] ? check_preempt_curr+0x62/0x90
[ 9680.126361] ? ttwu_do_wakeup+0x19/0x140
[ 9680.130355] ? try_to_wake_up+0x54/0x460
[ 9680.134366] ? reweight_entity+0x15b/0x1a0
[ 9680.138559] ? __queue_work+0x103/0x3f0
[ 9680.142472] ? update_dl_rq_load_avg+0x1cd/0x270
[ 9680.147194] ? timerqueue_del+0x1e/0x40
[ 9680.151092] ? __remove_hrtimer+0x35/0x70
[ 9680.155191] __hrtimer_run_queues+0x100/0x280
[ 9680.159658] hrtimer_interrupt+0x100/0x220
[ 9680.163835] smp_apic_timer_interrupt+0x6a/0x140
[ 9680.168555] apic_timer_interrupt+0xf/0x20
[ 9680.172756] </IRQ>

The XMM registers can only be collected by hardware events, not
software/probe events.

Add has_non_generic_regs() to check if non-generic registers, e.g. XMM
on X86, are applied for software/probe events. If yes, return
-EOPNOTSUPP.

The generic code define the mask of non-generic registers as 0 if arch
headers haven't overridden it.

Fixes: 878068ea270e ("perf/x86: Support outputting XMM registers")
Reported-by: Vince Weaver <[email protected]>
Signed-off-by: Kan Liang <[email protected]>
---

Changes since V1:
- Use macro PERF_REG_NON_GENERIC_MASK to replace function
- Avoid unnecessary abbreviations in comments
- Remove unnecessary bracket for return.

arch/x86/include/uapi/asm/perf_regs.h | 3 +++
include/linux/perf_regs.h | 8 ++++++++
kernel/events/core.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 41 insertions(+)

diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h
index ac67bbe..3a96971 100644
--- a/arch/x86/include/uapi/asm/perf_regs.h
+++ b/arch/x86/include/uapi/asm/perf_regs.h
@@ -52,4 +52,7 @@ enum perf_event_x86_regs {
/* These include both GPRs and XMMX registers */
PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2,
};
+
+#define PERF_REG_NON_GENERIC_MASK (~((1ULL << PERF_REG_X86_XMM0) - 1))
+
#endif /* _ASM_X86_PERF_REGS_H */
diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
index 4767474..1d794355 100644
--- a/include/linux/perf_regs.h
+++ b/include/linux/perf_regs.h
@@ -11,6 +11,11 @@ struct perf_regs {

#ifdef CONFIG_HAVE_PERF_REGS
#include <asm/perf_regs.h>
+
+#ifndef PERF_REG_NON_GENERIC_MASK
+#define PERF_REG_NON_GENERIC_MASK 0
+#endif
+
u64 perf_reg_value(struct pt_regs *regs, int idx);
int perf_reg_validate(u64 mask);
u64 perf_reg_abi(struct task_struct *task);
@@ -18,6 +23,9 @@ void perf_get_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs,
struct pt_regs *regs_user_copy);
#else
+
+#define PERF_REG_NON_GENERIC_MASK 0
+
static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
{
return 0;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index abbd4b3..4865bdf 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8457,6 +8457,12 @@ static void sw_perf_event_destroy(struct perf_event *event)
swevent_hlist_put();
}

+static inline bool has_non_generic_regs(struct perf_event *event)
+{
+ return (event->attr.sample_regs_user & PERF_REG_NON_GENERIC_MASK) ||
+ (event->attr.sample_regs_intr & PERF_REG_NON_GENERIC_MASK);
+}
+
static int perf_swevent_init(struct perf_event *event)
{
u64 event_id = event->attr.config;
@@ -8470,6 +8476,10 @@ static int perf_swevent_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
switch (event_id) {
case PERF_COUNT_SW_CPU_CLOCK:
case PERF_COUNT_SW_TASK_CLOCK:
@@ -8633,6 +8643,10 @@ static int perf_tp_event_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
err = perf_trace_init(event);
if (err)
return err;
@@ -8722,6 +8736,10 @@ static int perf_kprobe_event_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
err = perf_kprobe_init(event, is_retprobe);
if (err)
@@ -8782,6 +8800,10 @@ static int perf_uprobe_event_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
@@ -9562,6 +9584,10 @@ static int cpu_clock_event_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
perf_swevent_init_hrtimer(event);

return 0;
@@ -9643,6 +9669,10 @@ static int task_clock_event_init(struct perf_event *event)
if (has_branch_stack(event))
return -EOPNOTSUPP;

+ /* Only support generic registers */
+ if (has_non_generic_regs(event))
+ return -EOPNOTSUPP;
+
perf_swevent_init_hrtimer(event);

return 0;
--
2.7.4


2019-05-28 08:57:55

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events

On Mon, May 27, 2019 at 12:07:55PM -0700, [email protected] wrote:
> diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h
> index ac67bbe..3a96971 100644
> --- a/arch/x86/include/uapi/asm/perf_regs.h
> +++ b/arch/x86/include/uapi/asm/perf_regs.h
> @@ -52,4 +52,7 @@ enum perf_event_x86_regs {
> /* These include both GPRs and XMMX registers */
> PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2,
> };
> +
> +#define PERF_REG_NON_GENERIC_MASK (~((1ULL << PERF_REG_X86_XMM0) - 1))
> +
> #endif /* _ASM_X86_PERF_REGS_H */
> diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
> index 4767474..1d794355 100644
> --- a/include/linux/perf_regs.h
> +++ b/include/linux/perf_regs.h
> @@ -11,6 +11,11 @@ struct perf_regs {
>
> #ifdef CONFIG_HAVE_PERF_REGS
> #include <asm/perf_regs.h>
> +
> +#ifndef PERF_REG_NON_GENERIC_MASK
> +#define PERF_REG_NON_GENERIC_MASK 0
> +#endif
> +
> u64 perf_reg_value(struct pt_regs *regs, int idx);
> int perf_reg_validate(u64 mask);
> u64 perf_reg_abi(struct task_struct *task);
> @@ -18,6 +23,9 @@ void perf_get_regs_user(struct perf_regs *regs_user,
> struct pt_regs *regs,
> struct pt_regs *regs_user_copy);
> #else
> +
> +#define PERF_REG_NON_GENERIC_MASK 0
> +
> static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
> {
> return 0;

Much better than the last version; however..

> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index abbd4b3..4865bdf 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -8457,6 +8457,12 @@ static void sw_perf_event_destroy(struct perf_event *event)
> swevent_hlist_put();
> }
>
> +static inline bool has_non_generic_regs(struct perf_event *event)
> +{
> + return (event->attr.sample_regs_user & PERF_REG_NON_GENERIC_MASK) ||
> + (event->attr.sample_regs_intr & PERF_REG_NON_GENERIC_MASK);
> +}
> +
> static int perf_swevent_init(struct perf_event *event)
> {
> u64 event_id = event->attr.config;
> @@ -8470,6 +8476,10 @@ static int perf_swevent_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> switch (event_id) {
> case PERF_COUNT_SW_CPU_CLOCK:
> case PERF_COUNT_SW_TASK_CLOCK:
> @@ -8633,6 +8643,10 @@ static int perf_tp_event_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> err = perf_trace_init(event);
> if (err)
> return err;
> @@ -8722,6 +8736,10 @@ static int perf_kprobe_event_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
> err = perf_kprobe_init(event, is_retprobe);
> if (err)
> @@ -8782,6 +8800,10 @@ static int perf_uprobe_event_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
> ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
> err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
> @@ -9562,6 +9584,10 @@ static int cpu_clock_event_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> perf_swevent_init_hrtimer(event);
>
> return 0;
> @@ -9643,6 +9669,10 @@ static int task_clock_event_init(struct perf_event *event)
> if (has_branch_stack(event))
> return -EOPNOTSUPP;
>
> + /* Only support generic registers */
> + if (has_non_generic_regs(event))
> + return -EOPNOTSUPP;
> +
> perf_swevent_init_hrtimer(event);
>
> return 0;

I don't think this is anywhere near sufficient. What happens if we
request XMM regs for an uncore PMU ?

I'm thinking you want something along these lines...

---
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index a5436cee20b1..3ef1c2e0b177 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3281,7 +3281,13 @@ static int intel_pmu_hw_config(struct perf_event *event)

if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
- }
+
+ /* we only support extended (XMM) registers for sample_regs_intr */
+ if (event->attr.sample_regs_user & PERF_REGS_EXTENDED_MASK)
+ return -EOPNOTSUPP;
+
+ } else if (has_extended_regs(event))
+ return -EOPNOTSUPP;

if (needs_branch_stack(event)) {
ret = intel_pmu_setup_lbr_filter(event);
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 5e9bb246b3a6..4fae37f8c7c2 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2020,6 +2020,7 @@ void __init intel_ds_init(void)
PERF_SAMPLE_TIME;
x86_pmu.flags |= PMU_FL_PEBS_ALL;
pebs_qual = "-baseline";
+ x86_get_pmu()->capabilities |= PERF_PMU_CAP_EXTENDED_REGS;
} else {
/* Only basic record supported */
x86_pmu.pebs_no_xmm_regs = 1;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 0ab99c7b652d..2bca72f3028b 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -241,6 +241,7 @@ struct perf_event;
#define PERF_PMU_CAP_NO_INTERRUPT 0x01
#define PERF_PMU_CAP_NO_NMI 0x02
#define PERF_PMU_CAP_AUX_NO_SG 0x04
+#define PERF_PMU_CAP_EXTENDED_REGS 0x08
#define PERF_PMU_CAP_EXCLUSIVE 0x10
#define PERF_PMU_CAP_ITRACE 0x20
#define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40
diff --git a/kernel/events/core.c b/kernel/events/core.c
index abbd4b3b96c2..0c4872426b70 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10064,12 +10064,16 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
perf_event_ctx_unlock(event->group_leader, ctx);

if (!ret) {
+ if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
+ has_extended_regs(event))
+ ret = -EOPNOTSUPP;
+
if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
- event_has_any_exclude_flag(event)) {
- if (event->destroy)
- event->destroy(event);
+ event_has_any_exclude_flag(event))
ret = -EINVAL;
- }
+
+ if (ret && event->destroy)
+ event->destroy(event);
}

if (ret)

2019-05-28 13:36:44

by Liang, Kan

[permalink] [raw]
Subject: Re: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events



On 5/28/2019 4:56 AM, Peter Zijlstra wrote:
> On Mon, May 27, 2019 at 12:07:55PM -0700, [email protected] wrote:
>> diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h
>> index ac67bbe..3a96971 100644
>> --- a/arch/x86/include/uapi/asm/perf_regs.h
>> +++ b/arch/x86/include/uapi/asm/perf_regs.h
>> @@ -52,4 +52,7 @@ enum perf_event_x86_regs {
>> /* These include both GPRs and XMMX registers */
>> PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2,
>> };
>> +
>> +#define PERF_REG_NON_GENERIC_MASK (~((1ULL << PERF_REG_X86_XMM0) - 1))
>> +
>> #endif /* _ASM_X86_PERF_REGS_H */
>> diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
>> index 4767474..1d794355 100644
>> --- a/include/linux/perf_regs.h
>> +++ b/include/linux/perf_regs.h
>> @@ -11,6 +11,11 @@ struct perf_regs {
>>
>> #ifdef CONFIG_HAVE_PERF_REGS
>> #include <asm/perf_regs.h>
>> +
>> +#ifndef PERF_REG_NON_GENERIC_MASK
>> +#define PERF_REG_NON_GENERIC_MASK 0
>> +#endif
>> +
>> u64 perf_reg_value(struct pt_regs *regs, int idx);
>> int perf_reg_validate(u64 mask);
>> u64 perf_reg_abi(struct task_struct *task);
>> @@ -18,6 +23,9 @@ void perf_get_regs_user(struct perf_regs *regs_user,
>> struct pt_regs *regs,
>> struct pt_regs *regs_user_copy);
>> #else
>> +
>> +#define PERF_REG_NON_GENERIC_MASK 0
>> +
>> static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
>> {
>> return 0;
>
> Much better than the last version; however..
>
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index abbd4b3..4865bdf 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -8457,6 +8457,12 @@ static void sw_perf_event_destroy(struct perf_event *event)
>> swevent_hlist_put();
>> }
>>
>> +static inline bool has_non_generic_regs(struct perf_event *event)
>> +{
>> + return (event->attr.sample_regs_user & PERF_REG_NON_GENERIC_MASK) ||
>> + (event->attr.sample_regs_intr & PERF_REG_NON_GENERIC_MASK);
>> +}
>> +
>> static int perf_swevent_init(struct perf_event *event)
>> {
>> u64 event_id = event->attr.config;
>> @@ -8470,6 +8476,10 @@ static int perf_swevent_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> switch (event_id) {
>> case PERF_COUNT_SW_CPU_CLOCK:
>> case PERF_COUNT_SW_TASK_CLOCK:
>> @@ -8633,6 +8643,10 @@ static int perf_tp_event_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> err = perf_trace_init(event);
>> if (err)
>> return err;
>> @@ -8722,6 +8736,10 @@ static int perf_kprobe_event_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
>> err = perf_kprobe_init(event, is_retprobe);
>> if (err)
>> @@ -8782,6 +8800,10 @@ static int perf_uprobe_event_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
>> ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
>> err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
>> @@ -9562,6 +9584,10 @@ static int cpu_clock_event_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> perf_swevent_init_hrtimer(event);
>>
>> return 0;
>> @@ -9643,6 +9669,10 @@ static int task_clock_event_init(struct perf_event *event)
>> if (has_branch_stack(event))
>> return -EOPNOTSUPP;
>>
>> + /* Only support generic registers */
>> + if (has_non_generic_regs(event))
>> + return -EOPNOTSUPP;
>> +
>> perf_swevent_init_hrtimer(event);
>>
>> return 0;
>
> I don't think this is anywhere near sufficient. What happens if we
> request XMM regs for an uncore PMU ?
>

Uncore PMU doesn't support sampling. It will return -EINVAL.
There is no regs support for counting. The request will be ignored.

I think current check for uncore is good enough.

Thanks,
Kan

> I'm thinking you want something along these lines...
>
> ---
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index a5436cee20b1..3ef1c2e0b177 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -3281,7 +3281,13 @@ static int intel_pmu_hw_config(struct perf_event *event)
>
> if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
> event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
> - }
> +
> + /* we only support extended (XMM) registers for sample_regs_intr */
> + if (event->attr.sample_regs_user & PERF_REGS_EXTENDED_MASK)
> + return -EOPNOTSUPP;
> +
> + } else if (has_extended_regs(event))
> + return -EOPNOTSUPP;
>
> if (needs_branch_stack(event)) {
> ret = intel_pmu_setup_lbr_filter(event);
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index 5e9bb246b3a6..4fae37f8c7c2 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -2020,6 +2020,7 @@ void __init intel_ds_init(void)
> PERF_SAMPLE_TIME;
> x86_pmu.flags |= PMU_FL_PEBS_ALL;
> pebs_qual = "-baseline";
> + x86_get_pmu()->capabilities |= PERF_PMU_CAP_EXTENDED_REGS;
> } else {
> /* Only basic record supported */
> x86_pmu.pebs_no_xmm_regs = 1;
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 0ab99c7b652d..2bca72f3028b 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -241,6 +241,7 @@ struct perf_event;
> #define PERF_PMU_CAP_NO_INTERRUPT 0x01
> #define PERF_PMU_CAP_NO_NMI 0x02
> #define PERF_PMU_CAP_AUX_NO_SG 0x04
> +#define PERF_PMU_CAP_EXTENDED_REGS 0x08
> #define PERF_PMU_CAP_EXCLUSIVE 0x10
> #define PERF_PMU_CAP_ITRACE 0x20
> #define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index abbd4b3b96c2..0c4872426b70 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10064,12 +10064,16 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
> perf_event_ctx_unlock(event->group_leader, ctx);
>
> if (!ret) {
> + if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
> + has_extended_regs(event))
> + ret = -EOPNOTSUPP;
> +
> if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
> - event_has_any_exclude_flag(event)) {
> - if (event->destroy)
> - event->destroy(event);
> + event_has_any_exclude_flag(event))
> ret = -EINVAL;
> - }
> +
> + if (ret && event->destroy)
> + event->destroy(event);
> }
>
> if (ret)
>

2019-05-28 14:30:04

by Vince Weaver

[permalink] [raw]
Subject: Re: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events

On Tue, 28 May 2019, Peter Zijlstra wrote:

> On Tue, May 28, 2019 at 09:33:40AM -0400, Liang, Kan wrote:
> > Uncore PMU doesn't support sampling. It will return -EINVAL.
> > There is no regs support for counting. The request will be ignored.
> >
> > I think current check for uncore is good enough.
>
> breakpoints then.. There's also no guarantee you covered all software
> events, and the core rewrite will allow other per-task/sampling PMUs
> too.

possibly related, even with the patches applied, the skylake machine
eventually did still crash while fuzzing:

[133621.333101] BUG: unable to handle page fault for address: 00000001000000c8
[133621.333102] #PF: supervisor read access in kernel mode
[133621.333103] #PF: error_code(0x0000) - not-present page
[133621.333104] PGD 0 P4D 0
[133621.333106] Oops: 0000 [#1] SMP PTI
[133621.333108] CPU: 4 PID: 22203 Comm: perf_fuzzer Tainted: G W 5.2.0-rc1+ #39
[133621.333109] Hardware name: LENOVO 10FY0017US/SKYBAY, BIOS FWKT53A 06/06/2016
[133621.333109] RIP: 0010:perf_reg_value+0x1e/0x50
[133621.333111] Code: 00 48 b8 00 00 00 00 ff ff ff ff c3 0f 1f 44 00 00 8d 46 e0 83 f8 1f 77 1d 48 8b 97 a8 00 00 00 31 c0 48 85 d2 74 0e 48 63 f6 <48> 8b 84 f2 00 ff ff ff c3 31 c0 c3 83 fe 17 77 16 48 63 f6 8b 04
[133621.333112] RSP: 0000:fffffe00000d5a80 EFLAGS: 00010006
[133621.333113] RAX: 0000000000000000 RBX: 0000000000000039 RCX: 0000000000000039
[133621.333114] RDX: 0000000100000000 RSI: 0000000000000039 RDI: fffffe00000d5c88
[133621.333115] RBP: fffffe00000d5b38 R08: 0000000000000000 R09: 0000000000000000
[133621.333116] R10: 00000000bffffff0 R11: 0000000000000012 R12: fffffe00000d5c88
[133621.333117] R13: ffff99883253ed10 R14: 0000000000000050 R15: 0000000000000000
[133621.333118] FS: 00007fb9741d3540(0000) GS:ffff998835b00000(0000) knlGS:0000000000000000
[133621.333119] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[133621.333119] CR2: 00000001000000c8 CR3: 000000023333c004 CR4: 00000000003607e0
[133621.333120] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[133621.333121] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
[133621.333122] Call Trace:
[133621.333122] <NMI>
[133621.333123] perf_output_sample_regs+0x43/0xa0
[133621.333124] perf_output_sample+0x3aa/0x7a0
[133621.333125] perf_event_output_forward+0x53/0x80
[133621.333125] __perf_event_overflow+0x52/0xf0
[133621.333126] handle_pmi_common+0x1b3/0x240
[133621.333127] ? visit_groups_merge+0xeb/0x180
[133621.333127] ? native_write_msr+0xb/0x20
[133621.333128] ? native_write_msr+0x1a/0x20
[133621.333129] ? native_write_msr+0xc/0x20
[133621.333129] ? intel_pmu_lbr_read+0x29f/0x3d0
[133621.333130] ? intel_pmu_lbr_filter+0x7f/0x1f0
[133621.333131] intel_pmu_handle_irq+0xbf/0x160
[133621.333132] perf_event_nmi_handler+0x2d/0x50
[133621.333132] nmi_handle+0x63/0x110
[133621.333133] default_do_nmi+0x4e/0x100
[133621.333134] do_nmi+0x14d/0x1b0
[133621.333134] end_repeat_nmi+0x16/0x50
[133621.333135] RIP: 0010:visit_groups_merge+0xeb/0x180
[133621.333137] Code: c0 75 73 48 8d 7b 30 e8 c3 de 55 00 48 85 c0 0f 84 9a 00 00 00 48 89 c2 48 83 ea 30 74 10 8b b3 74 02 00 00 39 b0 44 02 00 00 <49> 0f 45 d7 48 89 55 00 48 8b 04 24 48 8b 5c 24 08 48 85 c0 48 89
[133621.333137] RSP: 0000:ffffb28f4c897e10 EFLAGS: 00000046
[133621.333139] RAX: ffff998833315830 RBX: ffff99882a17a000 RCX: 0000000000000001
[133621.333140] RDX: ffff998833315800 RSI: 0000000000000004 RDI: ffff99882a17a030
[133621.333140] RBP: ffffb28f4c897e18 R08: 0000000000000000 R09: ffff998835b26a80
[133621.333141] R10: ffff99882a17a000 R11: 0000000000000001 R12: ffffffffb6bb93b0
[133621.333142] R13: ffffb28f4c897e68 R14: ffffb28f4c897e10 R15: 0000000000000000
[133621.333143] ? __perf_event_disable+0x160/0x160
[133621.333144] ? visit_groups_merge+0xeb/0x180
[133621.333144] ? visit_groups_merge+0xeb/0x180
[133621.333145] </NMI>
[133621.333145] ctx_sched_in+0xb7/0x180
[133621.333146] __perf_event_task_sched_in+0x16e/0x1c0
[133621.333147] ? __switch_to_asm+0x40/0x70
[133621.333147] ? __switch_to_asm+0x34/0x70
[133621.333148] ? __switch_to_asm+0x40/0x70
[133621.333149] ? __switch_to_asm+0x34/0x70
[133621.333149] finish_task_switch+0xcd/0x270
[133621.333150] schedule_tail+0xb/0x50
[133621.333151] ret_from_fork+0x8/0x40
[133621.333151] Modules linked in: intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm irqbypass snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic crct10dif_pclmul crc32_pclmul ledtrig_audio ghash_clmulni_intel snd_hda_intel snd_hda_codec aesni_intel snd_hda_core aes_x86_64 crypto_simd snd_hwdep cryptd snd_pcm mei_me glue_helper snd_timer snd sg mei iTCO_wdt iTCO_vendor_support soundcore wmi_bmof tpm_tis evdev tpm_tis_core acpi_pad tpm rng_core pcspkr pcc_cpufreq fuse parport_pc sunrpc ppdev lp parport ip_tables x_tables autofs4 ext4 crc32c_generic crc16 mbcache jbd2 sr_mod sd_mod cdrom i915 i2c_algo_bit ahci libahci crc32c_intel xhci_pci libata drm_kms_helper i2c_i801 xhci_hcd e1000e drm scsi_mod usbcore fan thermal wmi video button
[133621.333183] CR2: 00000001000000c8
[133621.743913] ---[ end trace 7a151c3de6b000fc ]---
[133621.743913] RIP: 0010:perf_reg_value+0x1e/0x50
[133621.743913] Code: 00 48 b8 00 00 00 00 ff ff ff ff c3 0f 1f 44 00 00 8d 46 e0 83 f8 1f 77 1d 48 8b 97 a8 00 00 00 31 c0 48 85 d2 74 0e 48 63 f6 <48> 8b 84 f2 00 ff ff ff c3 31 c0 c3 83 fe 17 77 16 48 63 f6 8b 04
[133621.743913] RSP: 0000:fffffe00000d5a80 EFLAGS: 00010006
[133621.743914] RAX: 0000000000000000 RBX: 0000000000000039 RCX: 0000000000000039
[133621.743914] RDX: 0000000100000000 RSI: 0000000000000039 RDI: fffffe00000d5c88
[133621.743914] RBP: fffffe00000d5b38 R08: 0000000000000000 R09: 0000000000000000
[133621.743914] R10: 00000000bffffff0 R11: 0000000000000012 R12: fffffe00000d5c88
[133621.743915] R13: ffff99883253ed10 R14: 0000000000000050 R15: 0000000000000000
[133621.743915] FS: 00007fb9741d3540(0000) GS:ffff998835b00000(0000) knlGS:0000000000000000
[133621.743915] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[133621.743915] CR2: 00000001000000c8 CR3: 000000023333c004 CR4: 00000000003607e0
[133621.743915] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[133621.743916] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
[133621.743916] Kernel panic - not syncing: Fatal exception in interrupt
[133622.777346] Shutting down cpus with NMI
[133622.777347] Kernel Offset: 0x35a00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)

2019-05-28 14:30:57

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events

On Tue, May 28, 2019 at 09:33:40AM -0400, Liang, Kan wrote:
> Uncore PMU doesn't support sampling. It will return -EINVAL.
> There is no regs support for counting. The request will be ignored.
>
> I think current check for uncore is good enough.

breakpoints then.. There's also no guarantee you covered all software
events, and the core rewrite will allow other per-task/sampling PMUs
too.

The approach you take is just not complete, don't do that.

2019-05-28 14:32:17

by Liang, Kan

[permalink] [raw]
Subject: Re: [PATCH V2 1/3] perf/x86: Disable non generic regs for software/probe events



On 5/28/2019 10:05 AM, Peter Zijlstra wrote:
> On Tue, May 28, 2019 at 09:33:40AM -0400, Liang, Kan wrote:
>> Uncore PMU doesn't support sampling. It will return -EINVAL.
>> There is no regs support for counting. The request will be ignored.
>>
>> I think current check for uncore is good enough.
>
> breakpoints then.. There's also no guarantee you covered all software
> events, and the core rewrite will allow other per-task/sampling PMUs
> too.
>
> The approach you take is just not complete, don't do that.
>

OK. I will send V3 base on your proposed patches.

Thanks,
Kan