[PATCH] perf: Fix sibling iteration

From: Peter Zijlstra
Date: Thu Mar 15 2018 - 13:01:55 EST

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Subject: perf: Fix sibling iteration
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Thu Mar 15 17:36:56 CET 2018

Mark noticed that the change to sibling_list changed some iteration
semantics; because previously we used group_list as list entry,
sibling events would always have an empty sibling_list.

But because we now use sibling_list for both list head and list entry,
siblings will report as having siblings.

Fix this with a custom for_each_sibling_event() iterator.

Suggested-by: Mark Rutland <mark.rutland@xxxxxxx>
Reported-by: Mark Rutland <mark.rutland@xxxxxxx>
Fixes: 8343aae66167 ("perf/core: Remove perf_event::group_entry")
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
--- a/arch/alpha/kernel/perf_event.c
+++ b/arch/alpha/kernel/perf_event.c
@@ -351,7 +351,7 @@ static int collect_events(struct perf_ev
evtype[n] = group->hw.event_base;
current_idx[n++] = PMC_NO_INDEX;
}
- list_for_each_entry(pe, &group->sibling_list, sibling_list) {
+ for_each_sibling_event(pe, group) {
if (!is_software_event(pe) && pe->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
return -1;
--- a/arch/arm/mach-imx/mmdc.c
+++ b/arch/arm/mach-imx/mmdc.c
@@ -269,7 +269,7 @@ static bool mmdc_pmu_group_is_valid(stru
return false;
}

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (!mmdc_pmu_group_event_is_valid(sibling, pmu, &counter_mask))
return false;
}
--- a/arch/arm/mm/cache-l2x0-pmu.c
+++ b/arch/arm/mm/cache-l2x0-pmu.c
@@ -293,7 +293,7 @@ static bool l2x0_pmu_group_is_valid(stru
else if (!is_software_event(leader))
return false;

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (sibling->pmu == pmu)
num_hw++;
else if (!is_software_event(sibling))
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -711,7 +711,7 @@ static int validate_group(struct perf_ev
if (mipsxx_pmu_alloc_counter(&fake_cpuc, &leader->hw) < 0)
return -EINVAL;

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (mipsxx_pmu_alloc_counter(&fake_cpuc, &sibling->hw) < 0)
return -EINVAL;
}
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1426,7 +1426,7 @@ static int collect_events(struct perf_ev
flags[n] = group->hw.event_base;
events[n++] = group->hw.config;
}
- list_for_each_entry(event, &group->sibling_list, sibling_list) {
+ for_each_sibling_event(event, group) {
if (event->pmu->task_ctx_nr == perf_hw_context &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
--- a/arch/powerpc/perf/core-fsl-emb.c
+++ b/arch/powerpc/perf/core-fsl-emb.c
@@ -277,7 +277,7 @@ static int collect_events(struct perf_ev
ctrs[n] = group;
n++;
}
- list_for_each_entry(event, &group->sibling_list, sibling_list) {
+ for_each_sibling_event(event, group) {
if (!is_software_event(event) &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1342,7 +1342,7 @@ static int collect_events(struct perf_ev
events[n] = group->hw.event_base;
current_idx[n++] = PIC_NO_INDEX;
}
- list_for_each_entry(event, &group->sibling_list, sibling_list) {
+ for_each_sibling_event(event, group) {
if (!is_software_event(event) &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -990,7 +990,7 @@ static int collect_events(struct cpu_hw_
if (!dogrp)
return n;

- list_for_each_entry(event, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(event, leader) {
if (!is_x86_event(event) ||
event->state <= PERF_EVENT_STATE_OFF)
continue;
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -354,7 +354,7 @@ uncore_collect_events(struct intel_uncor
if (!dogrp)
return n;

- list_for_each_entry(event, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(event, leader) {
if (!is_box_event(box, event) ||
event->state <= PERF_EVENT_STATE_OFF)
continue;
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -1311,7 +1311,7 @@ validate_group(struct perf_event *event)
if (!validate_event(event->pmu, &fake_pmu, leader))
return -EINVAL;

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (!validate_event(event->pmu, &fake_pmu, sibling))
return -EINVAL;
}
--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -846,11 +846,11 @@ static int arm_ccn_pmu_event_init(struct
!is_software_event(event->group_leader))
return -EINVAL;

- list_for_each_entry(sibling, &event->group_leader->sibling_list,
- sibling_list)
+ for_each_sibling_event(sibling, event->group_leader) {
if (sibling->pmu != event->pmu &&
!is_software_event(sibling))
return -EINVAL;
+ }

return 0;
}
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -536,7 +536,7 @@ static bool dsu_pmu_validate_group(struc
memset(fake_hw.used_mask, 0, sizeof(fake_hw.used_mask));
if (!dsu_pmu_validate_event(event->pmu, &fake_hw, leader))
return false;
- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (!dsu_pmu_validate_event(event->pmu, &fake_hw, sibling))
return false;
}
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -311,7 +311,7 @@ validate_group(struct perf_event *event)
if (!validate_event(event->pmu, &fake_pmu, leader))
return -EINVAL;

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (!validate_event(event->pmu, &fake_pmu, sibling))
return -EINVAL;
}
--- a/drivers/perf/hisilicon/hisi_uncore_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c
@@ -82,7 +82,7 @@ static bool hisi_validate_event_group(st
counters++;
}

- list_for_each_entry(sibling, &event->group_leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, event->group_leader) {
if (is_software_event(sibling))
continue;
if (sibling->pmu != event->pmu)
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -534,8 +534,7 @@ static int l2_cache_event_init(struct pe
return -EINVAL;
}

- list_for_each_entry(sibling, &event->group_leader->sibling_list,
- sibling_list)
+ for_each_sibling_event(sibling, event->group_leader) {
if (sibling->pmu != event->pmu &&
!is_software_event(sibling)) {
dev_dbg_ratelimited(&l2cache_pmu->pdev->dev,
@@ -571,8 +570,7 @@ static int l2_cache_event_init(struct pe
return -EINVAL;
}

- list_for_each_entry(sibling, &event->group_leader->sibling_list,
- sibling_list) {
+ for_each_sibling_event(sibling, event->group_leader) {
if ((sibling != event) &&
!is_software_event(sibling) &&
(L2_EVT_GROUP(sibling->attr.config) ==
--- a/drivers/perf/qcom_l3_pmu.c
+++ b/drivers/perf/qcom_l3_pmu.c
@@ -468,7 +468,7 @@ static bool qcom_l3_cache__validate_even
counters = event_num_counters(event);
counters += event_num_counters(leader);

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sibling, leader) {
if (is_software_event(sibling))
continue;
if (sibling->pmu != event->pmu)
--- a/drivers/perf/xgene_pmu.c
+++ b/drivers/perf/xgene_pmu.c
@@ -949,11 +949,11 @@ static int xgene_perf_event_init(struct
!is_software_event(event->group_leader))
return -EINVAL;

- list_for_each_entry(sibling, &event->group_leader->sibling_list,
- sibling_list)
+ for_each_sibling_event(sibling, event->group_leader) {
if (sibling->pmu != event->pmu &&
!is_software_event(sibling))
return -EINVAL;
+ }

return 0;
}
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -536,6 +536,10 @@ struct pmu_event_list {
struct list_head list;
};

+#define for_each_sibling_event(sibling, event) \
+ if ((event)->group_leader == (event)) \
+ list_for_each_entry((sibling), &(event)->sibling_list, sibling_list)
+
/**
* struct perf_event - performance event kernel representation:
*/
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -643,7 +643,7 @@ static void perf_event_update_sibling_ti
{
struct perf_event *sibling;

- list_for_each_entry(sibling, &leader->sibling_list, sibling_list)
+ for_each_sibling_event(sibling, leader)
perf_event_update_time(sibling);
}

@@ -1828,7 +1828,7 @@ static void perf_group_attach(struct per

perf_event__header_size(group_leader);

- list_for_each_entry(pos, &group_leader->sibling_list, sibling_list)
+ for_each_sibling_event(pos, group_leader)
perf_event__header_size(pos);
}

@@ -1928,7 +1928,7 @@ static void perf_group_detach(struct per
out:
perf_event__header_size(event->group_leader);

- list_for_each_entry(tmp, &event->group_leader->sibling_list, sibling_list)
+ for_each_sibling_event(tmp, event->group_leader)
perf_event__header_size(tmp);
}

@@ -1951,13 +1951,13 @@ static inline int __pmu_filter_match(str
*/
static inline int pmu_filter_match(struct perf_event *event)
{
- struct perf_event *child;
+ struct perf_event *sibling;

if (!__pmu_filter_match(event))
return 0;

- list_for_each_entry(child, &event->sibling_list, sibling_list) {
- if (!__pmu_filter_match(child))
+ for_each_sibling_event(sibling, event) {
+ if (!__pmu_filter_match(sibling))
return 0;
}

@@ -2031,7 +2031,7 @@ group_sched_out(struct perf_event *group
/*
* Schedule out siblings (if any):
*/
- list_for_each_entry(event, &group_event->sibling_list, sibling_list)
+ for_each_sibling_event(event, group_event)
event_sched_out(event, cpuctx, ctx);

perf_pmu_enable(ctx->pmu);
@@ -2310,7 +2310,7 @@ group_sched_in(struct perf_event *group_
/*
* Schedule in siblings as one group (if any):
*/
- list_for_each_entry(event, &group_event->sibling_list, sibling_list) {
+ for_each_sibling_event(event, group_event) {
if (event_sched_in(event, cpuctx, ctx)) {
partial_group = event;
goto group_error;
@@ -2326,7 +2326,7 @@ group_sched_in(struct perf_event *group_
* partial group before returning:
* The events up to the failed event are scheduled out normally.
*/
- list_for_each_entry(event, &group_event->sibling_list, sibling_list) {
+ for_each_sibling_event(event, group_event) {
if (event == partial_group)
break;

@@ -3865,7 +3865,7 @@ static void __perf_event_read(void *info

pmu->read(event);

- list_for_each_entry(sub, &event->sibling_list, sibling_list) {
+ for_each_sibling_event(sub, event) {
if (sub->state == PERF_EVENT_STATE_ACTIVE) {
/*
* Use sibling's PMU rather than @event's since
@@ -4713,7 +4713,7 @@ static int __perf_read_group_add(struct
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);

- list_for_each_entry(sub, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sub, leader) {
values[n++] += perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
@@ -4907,7 +4907,7 @@ static void perf_event_for_each(struct p
event = event->group_leader;

perf_event_for_each_child(event, func);
- list_for_each_entry(sibling, &event->sibling_list, sibling_list)
+ for_each_sibling_event(sibling, event)
perf_event_for_each_child(sibling, func);
}

@@ -6079,7 +6079,7 @@ static void perf_output_read_group(struc

__output_copy(handle, values, n * sizeof(u64));

- list_for_each_entry(sub, &leader->sibling_list, sibling_list) {
+ for_each_sibling_event(sub, leader) {
n = 0;

if ((sub != event) &&
@@ -10664,8 +10664,7 @@ SYSCALL_DEFINE5(perf_event_open,
perf_remove_from_context(group_leader, 0);
put_ctx(gctx);

- list_for_each_entry(sibling, &group_leader->sibling_list,
- sibling_list) {
+ for_each_sibling_event(sibling, group_leader) {
perf_remove_from_context(sibling, 0);
put_ctx(gctx);
}
@@ -10686,8 +10685,7 @@ SYSCALL_DEFINE5(perf_event_open,
* By installing siblings first we NO-OP because they're not
* reachable through the group lists.
*/
- list_for_each_entry(sibling, &group_leader->sibling_list,
- sibling_list) {
+ for_each_sibling_event(sibling, group_leader) {
perf_event__state_init(sibling);
perf_install_in_context(ctx, sibling, sibling->cpu);
get_ctx(ctx);
@@ -11326,7 +11324,7 @@ static int inherit_group(struct perf_eve
* case inherit_event() will create individual events, similar to what
* perf_group_detach() would do anyway.
*/
- list_for_each_entry(sub, &parent_event->sibling_list, sibling_list) {
+ for_each_sibling_event(sub, parent_event) {
child_ctr = inherit_event(sub, parent, parent_ctx,
child, leader, child_ctx);
if (IS_ERR(child_ctr))

Next message: Lorenzo Pieralisi: "Re: [PATCH v4 1/2] PCI: hv: Serialize the present and eject work items"
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