perf: Fix sibling iteration

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.

Fixes: 8343aae66167 ("perf/core: Remove perf_event::group_entry")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: vincent.weaver@maine.edu
Cc: alexander.shishkin@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: alexey.budankov@linux.intel.com
Cc: valery.cherepennikov@intel.com
Cc: eranian@google.com
Cc: acme@redhat.com
Cc: linux-tip-commits@vger.kernel.org
Cc: davidcc@google.com
Cc: kan.liang@intel.com
Cc: Dmitry.Prohorov@intel.com
Cc: jolsa@redhat.com
Link: https://lkml.kernel.org/r/20180315170129.GX4043@hirez.programming.kicks-ass.net

19 files changed, 41 insertions, 40 deletions

diff --git a/arch/alpha/kernel/perf_event.c b/arch/alpha/kernel/perf_event.c
index 435864c24479..5613aa378a83 100644
--- a/arch/alpha/kernel/perf_event.c
+++ b/arch/alpha/kernel/perf_event.c
@@ -351,7 +351,7 @@ static int collect_events(struct perf_event *group, int max_count,
                 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;
diff --git a/arch/arm/mach-imx/mmdc.c b/arch/arm/mach-imx/mmdc.c
index 27a9ca20933e..04b3bf71de94 100644
--- 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(struct perf_event *event)
                         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;
         }
diff --git a/arch/arm/mm/cache-l2x0-pmu.c b/arch/arm/mm/cache-l2x0-pmu.c
index 3a89ea4c2b57..afe5b4c7b164 100644
--- 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(struct perf_event *event)
         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))
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 46097ff3208b..ee73550f0b9a 100644
--- 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_event *event)
         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;
         }
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 7c1f66050433..f8908ea4ea73 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1426,7 +1426,7 @@ static int collect_events(struct perf_event *group, int max_count,
                 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)
diff --git a/arch/powerpc/perf/core-fsl-emb.c b/arch/powerpc/perf/core-fsl-emb.c
index 94c2e63662c6..85f1d18e5fd3 100644
--- 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_event *group, int max_count,
                 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)
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index a0a86d369119..d3149baaa33c 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1342,7 +1342,7 @@ static int collect_events(struct perf_event *group, int max_count,
                 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)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 77a4125b6b1f..bfc8f43909c1 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -990,7 +990,7 @@ static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader,
         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;
diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 9e374cd22ad2..a7956fc7ca1d 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -354,7 +354,7 @@ uncore_collect_events(struct intel_uncore_box *box, struct perf_event *leader,
         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;
diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index c98435bdb64f..c4c0c8560cce 100644
--- 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;
         }
diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c
index 1c310a4be000..65b7e4042ece 100644
--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -846,11 +846,11 @@ static int arm_ccn_pmu_event_init(struct perf_event *event)
                         !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;
 }
diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
index 660680d78147..660cb8ac886a 100644
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -536,7 +536,7 @@ static bool dsu_pmu_validate_group(struct perf_event *event)
         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;
         }
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 628d7a7b9526..344e2083e941 100644
--- 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;
         }
diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c
index e3356087fd76..44df61397a38 100644
--- 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(struct perf_event *event)
                         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)
diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
index 5e535a718965..842135cf35a3 100644
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -534,14 +534,14 @@ static int l2_cache_event_init(struct perf_event *event)
                 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,
                                  "Can't create mixed PMU group\n");
                         return -EINVAL;
                 }
+        }
 
         cluster = get_cluster_pmu(l2cache_pmu, event->cpu);
         if (!cluster) {
@@ -571,8 +571,7 @@ static int l2_cache_event_init(struct perf_event *event)
                 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) ==
diff --git a/drivers/perf/qcom_l3_pmu.c b/drivers/perf/qcom_l3_pmu.c
index 5dedf4b1a552..2dc63d61f2ea 100644
--- a/drivers/perf/qcom_l3_pmu.c
+++ b/drivers/perf/qcom_l3_pmu.c
@@ -468,7 +468,7 @@ static bool qcom_l3_cache__validate_event_group(struct perf_event *event)
         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)
diff --git a/drivers/perf/xgene_pmu.c b/drivers/perf/xgene_pmu.c
index f1f4a56cab5e..6bdb1dad805f 100644
--- a/drivers/perf/xgene_pmu.c
+++ b/drivers/perf/xgene_pmu.c
@@ -949,11 +949,11 @@ static int xgene_perf_event_init(struct perf_event *event)
                         !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;
 }
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2bb200e1bbea..ff39ab011376 100644
--- 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:
  */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3b4c7792a6ac..4d7a460d6669 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -643,7 +643,7 @@ static void perf_event_update_sibling_time(struct perf_event *leader)
 {
         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 perf_event *event)
 
         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 perf_event *event)
 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(struct perf_event *event)
  */
 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_event,
         /*
          * 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_event,
         /*
          * 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_error:
          * 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;
 
@@ -3863,7 +3863,7 @@ 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
@@ -4711,7 +4711,7 @@ static int __perf_read_group_add(struct perf_event *leader,
         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);
@@ -4905,7 +4905,7 @@ static void perf_event_for_each(struct perf_event *event,
         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);
 }
 
@@ -6077,7 +6077,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 
         __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) &&
@@ -10662,8 +10662,7 @@ 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);
                 }
@@ -10684,8 +10683,7 @@ 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);
@@ -11324,7 +11322,7 @@ static int inherit_group(struct perf_event *parent_event,
          * 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))