[PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[Yabin Cui]

Hello,

We use helper functions to save raw data, callchain and branch stack in
perf_sample_data. These functions update perf_sample_data->dyn_size without
checking event->attr.sample_type, which may result in unused space
allocated in sample records. To prevent this from happening, this patchset
enforces checking sample_type of an event in these helper functions.

Thanks,
Yabin


Changes since v1:
 - Check event->attr.sample_type & PERF_SAMPLE_RAW before
   calling perf_sample_save_raw_data().
 - Subject has been changed to reflect the change of solution.

Changes since v2:
 - Move sample_type check into perf_sample_save_raw_data().
 - (New patch) Move sample_type check into perf_sample_save_callchain().
 - (New patch) Move sample_type check into perf_sample_save_brstack().

Changes since v3:
 - Fix -Werror=implicit-function-declaration by moving has_branch_stack().

Changes since v4:
 - Give a warning if data->sample_flags is already set when calling the
   helper functions.

Original commit message from v1:
  perf/core: Trim dyn_size if raw data is absent

Original commit message from v2/v3:
  perf/core: Save raw sample data conditionally based on sample type


Yabin Cui (3):
  perf/core: Save raw sample data conditionally based on sample type
  perf/core: Check sample_type in perf_sample_save_callchain
  perf/core: Check sample_type in perf_sample_save_brstack

 arch/s390/kernel/perf_cpum_cf.c    |  2 +-
 arch/s390/kernel/perf_pai_crypto.c |  2 +-
 arch/s390/kernel/perf_pai_ext.c    |  2 +-
 arch/x86/events/amd/core.c         |  3 +--
 arch/x86/events/amd/ibs.c          |  5 ++---
 arch/x86/events/core.c             |  3 +--
 arch/x86/events/intel/ds.c         |  9 +++-----
 include/linux/perf_event.h         | 26 +++++++++++++++++-----
 kernel/events/core.c               | 35 +++++++++++++++---------------
 kernel/trace/bpf_trace.c           | 11 +++++-----
 10 files changed, 55 insertions(+), 43 deletions(-)

-- 
2.45.0.rc1.225.g2a3ae87e7f-goog

[PATCH v5 1/3] perf/core: Save raw sample data conditionally based on sample type

[Yabin Cui]

Currently, space for raw sample data is always allocated within sample
records for both BPF output and tracepoint events. This leads to unused
space in sample records when raw sample data is not requested.

This patch enforces checking sample type of an event in
perf_sample_save_raw_data(). So raw sample data will only be saved if
explicitly requested, reducing overhead when it is not needed.

Fixes: 0a9081cf0a11 ("perf/core: Add perf_sample_save_raw_data() helper")
Signed-off-by: Yabin Cui <yabinc@google.com>
---
 arch/s390/kernel/perf_cpum_cf.c    |  2 +-
 arch/s390/kernel/perf_pai_crypto.c |  2 +-
 arch/s390/kernel/perf_pai_ext.c    |  2 +-
 arch/x86/events/amd/ibs.c          |  2 +-
 include/linux/perf_event.h         |  6 +++++
 kernel/events/core.c               | 35 +++++++++++++++---------------
 kernel/trace/bpf_trace.c           | 11 +++++-----
 7 files changed, 34 insertions(+), 26 deletions(-)

diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 1434642e9cba..9bf9464109e9 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -971,7 +971,7 @@ static int cfdiag_push_sample(struct perf_event *event,
 	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
 		raw.frag.size = cpuhw->usedss;
 		raw.frag.data = cpuhw->stop;
-		perf_sample_save_raw_data(&data, &raw);
+		perf_sample_save_raw_data(&data, event, &raw);
 	}
 
 	overflow = perf_event_overflow(event, &data, &regs);
diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index 4ad472d130a3..2fb8aeba4872 100644
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -444,7 +444,7 @@ static int paicrypt_push_sample(size_t rawsize, struct paicrypt_map *cpump,
 	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
 		raw.frag.size = rawsize;
 		raw.frag.data = cpump->save;
-		perf_sample_save_raw_data(&data, &raw);
+		perf_sample_save_raw_data(&data, event, &raw);
 	}
 
 	overflow = perf_event_overflow(event, &data, &regs);
diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index a6da7e0cc7a6..b2914df2107a 100644
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -458,7 +458,7 @@ static int paiext_push_sample(size_t rawsize, struct paiext_map *cpump,
 	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
 		raw.frag.size = rawsize;
 		raw.frag.data = cpump->save;
-		perf_sample_save_raw_data(&data, &raw);
+		perf_sample_save_raw_data(&data, event, &raw);
 	}
 
 	overflow = perf_event_overflow(event, &data, &regs);
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index e91970b01d62..c3a2f6f57770 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -1118,7 +1118,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 				.data = ibs_data.data,
 			},
 		};
-		perf_sample_save_raw_data(&data, &raw);
+		perf_sample_save_raw_data(&data, event, &raw);
 	}
 
 	if (perf_ibs == &perf_ibs_op)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index a5304ae8c654..fefac1a57b56 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1243,12 +1243,18 @@ static inline void perf_sample_save_callchain(struct perf_sample_data *data,
 }
 
 static inline void perf_sample_save_raw_data(struct perf_sample_data *data,
+					     struct perf_event *event,
 					     struct perf_raw_record *raw)
 {
 	struct perf_raw_frag *frag = &raw->frag;
 	u32 sum = 0;
 	int size;
 
+	if (!(event->attr.sample_type & PERF_SAMPLE_RAW))
+		return;
+	if (WARN_ON_ONCE(data->sample_flags & PERF_SAMPLE_RAW))
+		return;
+
 	do {
 		sum += frag->size;
 		if (perf_raw_frag_last(frag))
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6b0a66ed2ae3..28e4e777e82a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10228,9 +10228,9 @@ static struct pmu perf_tracepoint = {
 };
 
 static int perf_tp_filter_match(struct perf_event *event,
-				struct perf_sample_data *data)
+				struct perf_raw_record *raw)
 {
-	void *record = data->raw->frag.data;
+	void *record = raw->frag.data;
 
 	/* only top level events have filters set */
 	if (event->parent)
@@ -10242,7 +10242,7 @@ static int perf_tp_filter_match(struct perf_event *event,
 }
 
 static int perf_tp_event_match(struct perf_event *event,
-				struct perf_sample_data *data,
+				struct perf_raw_record *raw,
 				struct pt_regs *regs)
 {
 	if (event->hw.state & PERF_HES_STOPPED)
@@ -10253,7 +10253,7 @@ static int perf_tp_event_match(struct perf_event *event,
 	if (event->attr.exclude_kernel && !user_mode(regs))
 		return 0;
 
-	if (!perf_tp_filter_match(event, data))
+	if (!perf_tp_filter_match(event, raw))
 		return 0;
 
 	return 1;
@@ -10279,6 +10279,7 @@ EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
 static void __perf_tp_event_target_task(u64 count, void *record,
 					struct pt_regs *regs,
 					struct perf_sample_data *data,
+					struct perf_raw_record *raw,
 					struct perf_event *event)
 {
 	struct trace_entry *entry = record;
@@ -10288,13 +10289,17 @@ static void __perf_tp_event_target_task(u64 count, void *record,
 	/* Cannot deliver synchronous signal to other task. */
 	if (event->attr.sigtrap)
 		return;
-	if (perf_tp_event_match(event, data, regs))
+	if (perf_tp_event_match(event, raw, regs)) {
+		perf_sample_data_init(data, 0, 0);
+		perf_sample_save_raw_data(data, event, raw);
 		perf_swevent_event(event, count, data, regs);
+	}
 }
 
 static void perf_tp_event_target_task(u64 count, void *record,
 				      struct pt_regs *regs,
 				      struct perf_sample_data *data,
+				      struct perf_raw_record *raw,
 				      struct perf_event_context *ctx)
 {
 	unsigned int cpu = smp_processor_id();
@@ -10302,15 +10307,15 @@ static void perf_tp_event_target_task(u64 count, void *record,
 	struct perf_event *event, *sibling;
 
 	perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
-		__perf_tp_event_target_task(count, record, regs, data, event);
+		__perf_tp_event_target_task(count, record, regs, data, raw, event);
 		for_each_sibling_event(sibling, event)
-			__perf_tp_event_target_task(count, record, regs, data, sibling);
+			__perf_tp_event_target_task(count, record, regs, data, raw, sibling);
 	}
 
 	perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
-		__perf_tp_event_target_task(count, record, regs, data, event);
+		__perf_tp_event_target_task(count, record, regs, data, raw, event);
 		for_each_sibling_event(sibling, event)
-			__perf_tp_event_target_task(count, record, regs, data, sibling);
+			__perf_tp_event_target_task(count, record, regs, data, raw, sibling);
 	}
 }
 
@@ -10328,15 +10333,10 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
 		},
 	};
 
-	perf_sample_data_init(&data, 0, 0);
-	perf_sample_save_raw_data(&data, &raw);
-
 	perf_trace_buf_update(record, event_type);
 
 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
-		if (perf_tp_event_match(event, &data, regs)) {
-			perf_swevent_event(event, count, &data, regs);
-
+		if (perf_tp_event_match(event, &raw, regs)) {
 			/*
 			 * Here use the same on-stack perf_sample_data,
 			 * some members in data are event-specific and
@@ -10346,7 +10346,8 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
 			 * because data->sample_flags is set.
 			 */
 			perf_sample_data_init(&data, 0, 0);
-			perf_sample_save_raw_data(&data, &raw);
+			perf_sample_save_raw_data(&data, event, &raw);
+			perf_swevent_event(event, count, &data, regs);
 		}
 	}
 
@@ -10363,7 +10364,7 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
 			goto unlock;
 
 		raw_spin_lock(&ctx->lock);
-		perf_tp_event_target_task(count, record, regs, &data, ctx);
+		perf_tp_event_target_task(count, record, regs, &data, &raw, ctx);
 		raw_spin_unlock(&ctx->lock);
 unlock:
 		rcu_read_unlock();
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index f5154c051d2c..a7ec7a3eb7e1 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -620,7 +620,8 @@ static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
 
 static __always_inline u64
 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
-			u64 flags, struct perf_sample_data *sd)
+			u64 flags, struct perf_raw_record *raw,
+			struct perf_sample_data *sd)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	unsigned int cpu = smp_processor_id();
@@ -645,6 +646,8 @@ __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
 	if (unlikely(event->oncpu != cpu))
 		return -EOPNOTSUPP;
 
+	perf_sample_save_raw_data(sd, event, raw);
+
 	return perf_event_output(event, sd, regs);
 }
 
@@ -688,9 +691,8 @@ BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
 	}
 
 	perf_sample_data_init(sd, 0, 0);
-	perf_sample_save_raw_data(sd, &raw);
 
-	err = __bpf_perf_event_output(regs, map, flags, sd);
+	err = __bpf_perf_event_output(regs, map, flags, &raw, sd);
 out:
 	this_cpu_dec(bpf_trace_nest_level);
 	preempt_enable();
@@ -749,9 +751,8 @@ u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 
 	perf_fetch_caller_regs(regs);
 	perf_sample_data_init(sd, 0, 0);
-	perf_sample_save_raw_data(sd, &raw);
 
-	ret = __bpf_perf_event_output(regs, map, flags, sd);
+	ret = __bpf_perf_event_output(regs, map, flags, &raw, sd);
 out:
 	this_cpu_dec(bpf_event_output_nest_level);
 	preempt_enable();
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog

[PATCH v5 2/3] perf/core: Check sample_type in perf_sample_save_callchain

[Yabin Cui]

Check sample_type in perf_sample_save_callchain() to prevent
saving callchain data when it isn't required.

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Yabin Cui <yabinc@google.com>
---
 arch/x86/events/amd/ibs.c  | 3 +--
 arch/x86/events/intel/ds.c | 6 ++----
 include/linux/perf_event.h | 5 +++++
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index c3a2f6f57770..f02939655b2a 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -1129,8 +1129,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 	 * recorded as part of interrupt regs. Thus we need to use rip from
 	 * interrupt regs while unwinding call stack.
 	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(&data, event, iregs);
+	perf_sample_save_callchain(&data, event, iregs);
 
 	throttle = perf_event_overflow(event, &data, &regs);
 out:
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index e010bfed8417..c2b5585aa6d1 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1655,8 +1655,7 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(data, event, iregs);
+	perf_sample_save_callchain(data, event, iregs);
 
 	/*
 	 * We use the interrupt regs as a base because the PEBS record does not
@@ -1823,8 +1822,7 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(data, event, iregs);
+	perf_sample_save_callchain(data, event, iregs);
 
 	*regs = *iregs;
 	/* The ip in basic is EventingIP */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index fefac1a57b56..bda066c33120 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1235,6 +1235,11 @@ static inline void perf_sample_save_callchain(struct perf_sample_data *data,
 {
 	int size = 1;
 
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
+		return;
+	if (WARN_ON_ONCE(data->sample_flags & PERF_SAMPLE_CALLCHAIN))
+		return;
+
 	data->callchain = perf_callchain(event, regs);
 	size += data->callchain->nr;
 
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog

[PATCH v5 3/3] perf/core: Check sample_type in perf_sample_save_brstack

[Yabin Cui]

Check sample_type in perf_sample_save_brstack() to prevent
saving branch stack data when it isn't required.

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Yabin Cui <yabinc@google.com>
---
 arch/x86/events/amd/core.c |  3 +--
 arch/x86/events/core.c     |  3 +--
 arch/x86/events/intel/ds.c |  3 +--
 include/linux/perf_event.h | 15 ++++++++++-----
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 1fc4ce44e743..f71a9ef932c5 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -998,8 +998,7 @@ static int amd_pmu_v2_handle_irq(struct pt_regs *regs)
 		if (!x86_perf_event_set_period(event))
 			continue;
 
-		if (has_branch_stack(event))
-			perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
+		perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
 
 		if (perf_event_overflow(event, &data, regs))
 			x86_pmu_stop(event, 0);
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 5b0dd07b1ef1..ff5577315938 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1702,8 +1702,7 @@ int x86_pmu_handle_irq(struct pt_regs *regs)
 
 		perf_sample_data_init(&data, 0, event->hw.last_period);
 
-		if (has_branch_stack(event))
-			perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
+		perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
 
 		if (perf_event_overflow(event, &data, regs))
 			x86_pmu_stop(event, 0);
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index c2b5585aa6d1..f25236ffa28f 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1754,8 +1754,7 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
 	if (x86_pmu.intel_cap.pebs_format >= 3)
 		setup_pebs_time(event, data, pebs->tsc);
 
-	if (has_branch_stack(event))
-		perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL);
+	perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL);
 }
 
 static void adaptive_pebs_save_regs(struct pt_regs *regs,
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index bda066c33120..f6637f3cbe84 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1276,6 +1276,11 @@ static inline void perf_sample_save_raw_data(struct perf_sample_data *data,
 	data->sample_flags |= PERF_SAMPLE_RAW;
 }
 
+static inline bool has_branch_stack(struct perf_event *event)
+{
+	return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
+}
+
 static inline void perf_sample_save_brstack(struct perf_sample_data *data,
 					    struct perf_event *event,
 					    struct perf_branch_stack *brs,
@@ -1283,6 +1288,11 @@ static inline void perf_sample_save_brstack(struct perf_sample_data *data,
 {
 	int size = sizeof(u64); /* nr */
 
+	if (!has_branch_stack(event))
+		return;
+	if (WARN_ON_ONCE(data->sample_flags & PERF_SAMPLE_BRANCH_STACK))
+		return;
+
 	if (branch_sample_hw_index(event))
 		size += sizeof(u64);
 	size += brs->nr * sizeof(struct perf_branch_entry);
@@ -1658,11 +1668,6 @@ extern void perf_bp_event(struct perf_event *event, void *data);
 # define perf_arch_bpf_user_pt_regs(regs) regs
 #endif
 
-static inline bool has_branch_stack(struct perf_event *event)
-{
-	return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
-}
-
 static inline bool needs_branch_stack(struct perf_event *event)
 {
 	return event->attr.branch_sample_type != 0;
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog

Re: [PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[Namhyung Kim]

Hello,

On Wed, May 15, 2024 at 12:36 PM Yabin Cui <yabinc@google.com> wrote:
>
> Hello,
>
> We use helper functions to save raw data, callchain and branch stack in
> perf_sample_data. These functions update perf_sample_data->dyn_size without
> checking event->attr.sample_type, which may result in unused space
> allocated in sample records. To prevent this from happening, this patchset
> enforces checking sample_type of an event in these helper functions.
>
> Thanks,
> Yabin
>
>
> Changes since v1:
>  - Check event->attr.sample_type & PERF_SAMPLE_RAW before
>    calling perf_sample_save_raw_data().
>  - Subject has been changed to reflect the change of solution.
>
> Changes since v2:
>  - Move sample_type check into perf_sample_save_raw_data().
>  - (New patch) Move sample_type check into perf_sample_save_callchain().
>  - (New patch) Move sample_type check into perf_sample_save_brstack().
>
> Changes since v3:
>  - Fix -Werror=implicit-function-declaration by moving has_branch_stack().
>
> Changes since v4:
>  - Give a warning if data->sample_flags is already set when calling the
>    helper functions.
>
> Original commit message from v1:
>   perf/core: Trim dyn_size if raw data is absent
>
> Original commit message from v2/v3:
>   perf/core: Save raw sample data conditionally based on sample type
>
>
> Yabin Cui (3):
>   perf/core: Save raw sample data conditionally based on sample type
>   perf/core: Check sample_type in perf_sample_save_callchain
>   perf/core: Check sample_type in perf_sample_save_brstack

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


>
>  arch/s390/kernel/perf_cpum_cf.c    |  2 +-
>  arch/s390/kernel/perf_pai_crypto.c |  2 +-
>  arch/s390/kernel/perf_pai_ext.c    |  2 +-
>  arch/x86/events/amd/core.c         |  3 +--
>  arch/x86/events/amd/ibs.c          |  5 ++---
>  arch/x86/events/core.c             |  3 +--
>  arch/x86/events/intel/ds.c         |  9 +++-----
>  include/linux/perf_event.h         | 26 +++++++++++++++++-----
>  kernel/events/core.c               | 35 +++++++++++++++---------------
>  kernel/trace/bpf_trace.c           | 11 +++++-----
>  10 files changed, 55 insertions(+), 43 deletions(-)
>
> --
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>

Re: [PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[Yabin Cui]

On Wed, May 22, 2024 at 9:27 AM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hello,
>
> On Wed, May 15, 2024 at 12:36 PM Yabin Cui <yabinc@google.com> wrote:
> >
> > Hello,
> >
> > We use helper functions to save raw data, callchain and branch stack in
> > perf_sample_data. These functions update perf_sample_data->dyn_size without
> > checking event->attr.sample_type, which may result in unused space
> > allocated in sample records. To prevent this from happening, this patchset
> > enforces checking sample_type of an event in these helper functions.
> >
> > Thanks,
> > Yabin
> >
> >
> > Changes since v1:
> >  - Check event->attr.sample_type & PERF_SAMPLE_RAW before
> >    calling perf_sample_save_raw_data().
> >  - Subject has been changed to reflect the change of solution.
> >
> > Changes since v2:
> >  - Move sample_type check into perf_sample_save_raw_data().
> >  - (New patch) Move sample_type check into perf_sample_save_callchain().
> >  - (New patch) Move sample_type check into perf_sample_save_brstack().
> >
> > Changes since v3:
> >  - Fix -Werror=implicit-function-declaration by moving has_branch_stack().
> >
> > Changes since v4:
> >  - Give a warning if data->sample_flags is already set when calling the
> >    helper functions.
> >
> > Original commit message from v1:
> >   perf/core: Trim dyn_size if raw data is absent
> >
> > Original commit message from v2/v3:
> >   perf/core: Save raw sample data conditionally based on sample type
> >
> >
> > Yabin Cui (3):
> >   perf/core: Save raw sample data conditionally based on sample type
> >   perf/core: Check sample_type in perf_sample_save_callchain
> >   perf/core: Check sample_type in perf_sample_save_brstack
>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
>
> Thanks,
> Namhyung
>

Hi performance events subsystem maintainers,

The v5 patches were modified based on Peter's comments on the v4
patches. I'd be grateful if you could take a look when you have a
moment.
Thank you for your time and consideration.

Thanks,
Yabin

> >
> >  arch/s390/kernel/perf_cpum_cf.c    |  2 +-
> >  arch/s390/kernel/perf_pai_crypto.c |  2 +-
> >  arch/s390/kernel/perf_pai_ext.c    |  2 +-
> >  arch/x86/events/amd/core.c         |  3 +--
> >  arch/x86/events/amd/ibs.c          |  5 ++---
> >  arch/x86/events/core.c             |  3 +--
> >  arch/x86/events/intel/ds.c         |  9 +++-----
> >  include/linux/perf_event.h         | 26 +++++++++++++++++-----
> >  kernel/events/core.c               | 35 +++++++++++++++---------------
> >  kernel/trace/bpf_trace.c           | 11 +++++-----
> >  10 files changed, 55 insertions(+), 43 deletions(-)
> >
> > --
> > 2.45.0.rc1.225.g2a3ae87e7f-goog
> >

Re: [PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[Yabin Cui]

On Tue, May 28, 2024 at 10:59 AM Yabin Cui <yabinc@google.com> wrote:
>
> On Wed, May 22, 2024 at 9:27 AM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > Hello,
> >
> > On Wed, May 15, 2024 at 12:36 PM Yabin Cui <yabinc@google.com> wrote:
> > >
> > > Hello,
> > >
> > > We use helper functions to save raw data, callchain and branch stack in
> > > perf_sample_data. These functions update perf_sample_data->dyn_size without
> > > checking event->attr.sample_type, which may result in unused space
> > > allocated in sample records. To prevent this from happening, this patchset
> > > enforces checking sample_type of an event in these helper functions.
> > >
> > > Thanks,
> > > Yabin
> > >
> > >
> > > Changes since v1:
> > >  - Check event->attr.sample_type & PERF_SAMPLE_RAW before
> > >    calling perf_sample_save_raw_data().
> > >  - Subject has been changed to reflect the change of solution.
> > >
> > > Changes since v2:
> > >  - Move sample_type check into perf_sample_save_raw_data().
> > >  - (New patch) Move sample_type check into perf_sample_save_callchain().
> > >  - (New patch) Move sample_type check into perf_sample_save_brstack().
> > >
> > > Changes since v3:
> > >  - Fix -Werror=implicit-function-declaration by moving has_branch_stack().
> > >
> > > Changes since v4:
> > >  - Give a warning if data->sample_flags is already set when calling the
> > >    helper functions.
> > >
> > > Original commit message from v1:
> > >   perf/core: Trim dyn_size if raw data is absent
> > >
> > > Original commit message from v2/v3:
> > >   perf/core: Save raw sample data conditionally based on sample type
> > >
> > >
> > > Yabin Cui (3):
> > >   perf/core: Save raw sample data conditionally based on sample type
> > >   perf/core: Check sample_type in perf_sample_save_callchain
> > >   perf/core: Check sample_type in perf_sample_save_brstack
> >
> > Acked-by: Namhyung Kim <namhyung@kernel.org>
> >
> > Thanks,
> > Namhyung
> >
>
> Hi performance events subsystem maintainers,
>
> The v5 patches were modified based on Peter's comments on the v4
> patches. I'd be grateful if you could take a look when you have a
> moment.
> Thank you for your time and consideration.
>
> Thanks,
> Yabin
>

Hi, friendly ping again for review?

> > >
> > >  arch/s390/kernel/perf_cpum_cf.c    |  2 +-
> > >  arch/s390/kernel/perf_pai_crypto.c |  2 +-
> > >  arch/s390/kernel/perf_pai_ext.c    |  2 +-
> > >  arch/x86/events/amd/core.c         |  3 +--
> > >  arch/x86/events/amd/ibs.c          |  5 ++---
> > >  arch/x86/events/core.c             |  3 +--
> > >  arch/x86/events/intel/ds.c         |  9 +++-----
> > >  include/linux/perf_event.h         | 26 +++++++++++++++++-----
> > >  kernel/events/core.c               | 35 +++++++++++++++---------------
> > >  kernel/trace/bpf_trace.c           | 11 +++++-----
> > >  10 files changed, 55 insertions(+), 43 deletions(-)
> > >
> > > --
> > > 2.45.0.rc1.225.g2a3ae87e7f-goog
> > >

Re: [PATCH v5 0/3] perf/core: Check sample_type in sample data saving helper functions

[Ingo Molnar]

* Yabin Cui <yabinc@google.com> wrote:

> Hi, friendly ping again for review?

Sorry about the delay, this feel between the cracks. I've applied your 
series to tip:perf/core, nice work and thanks a lot!

	Ingo