[PATCH] perf core: Get rid of 'uses dynamic stack allocation' warning

From: Wang Nan
Date: Fri Jan 22 2016 - 01:53:33 EST

Next message: Wenyou Yang: "[PATCH v7 0/2] power: act8945a: add charger driver for the sub-device of ACT8945A MFD"
Previous message: Alexey Kardashevskiy: "Re: [PATCH kernel] vfio: Only check for bus IOMMU when NOIOMMU is selected"
Next in thread: kbuild test robot: "Re: [PATCH] perf core: Get rid of 'uses dynamic stack allocation' warning"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On s390 with CONFIG_WARN_DYNAMIC_STACK set, 'uses dynamic stack
allocation' warning is issued when defining 'struct perf_sample_data'
local variable.

This patch suppress this warning by allocating extra 255 bytes and
compute aligned pointer manually.

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---

I'm not confident on this patch because I know nothing about s390,
and the extra 255 bytes seems too large. Please simply ignore this
patch if it is inappropriate.

KBuild robot say:

kernel/events/ring_buffer.c: In function 'perf_output_begin':
kernel/events/ring_buffer.c:251:1: warning: 'perf_output_begin' uses dynamic stack allocation
}
^

---
include/linux/perf_event.h | 11 ++++++
kernel/events/core.c | 86 ++++++++++++++++++++++-----------------------
kernel/events/ring_buffer.c | 6 ++--
3 files changed, 57 insertions(+), 46 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f9828a4..263b6ef 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -797,6 +797,17 @@ struct perf_sample_data {
u64 stack_user_size;
} ____cacheline_aligned;

+#ifdef CONFIG_WARN_DYNAMIC_STACK
+#define DEFINE_PERF_SAMPLE_DATA_ALIGNED(pn, an) \
+ u8 an[SMP_CACHE_BYTES - 1 + sizeof(struct perf_sample_data)]; \
+ struct perf_sample_data *pn = \
+ (struct perf_sample_data *)PTR_ALIGN(&an, SMP_CACHE_BYTES)
+#else
+#define DEFINE_PERF_SAMPLE_DATA_ALIGNED(pn, an) \
+ struct perf_sample_data an; \
+ struct perf_sample_data *pn = &an;
+#endif
+
/* default value for data source */
#define PERF_MEM_NA (PERF_MEM_S(OP, NA) |\
PERF_MEM_S(LVL, NA) |\
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9e9c84da..36abe60 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5580,7 +5580,7 @@ perf_event_read_event(struct perf_event *event,
struct task_struct *task)
{
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
struct perf_read_event read_event = {
.header = {
.type = PERF_RECORD_READ,
@@ -5592,14 +5592,14 @@ perf_event_read_event(struct perf_event *event,
};
int ret;

- perf_event_header__init_id(&read_event.header, &sample, event);
+ perf_event_header__init_id(&read_event.header, psample, event);
ret = perf_output_begin(&handle, event, read_event.header.size);
if (ret)
return;

perf_output_put(&handle, read_event);
perf_output_read(&handle, event);
- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
}
@@ -5704,14 +5704,14 @@ static void perf_event_task_output(struct perf_event *event,
{
struct perf_task_event *task_event = data;
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
struct task_struct *task = task_event->task;
int ret, size = task_event->event_id.header.size;

if (!perf_event_task_match(event))
return;

- perf_event_header__init_id(&task_event->event_id.header, &sample, event);
+ perf_event_header__init_id(&task_event->event_id.header, psample, event);

ret = perf_output_begin(&handle, event,
task_event->event_id.header.size);
@@ -5728,7 +5728,7 @@ static void perf_event_task_output(struct perf_event *event,

perf_output_put(&handle, task_event->event_id);

- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
out:
@@ -5800,14 +5800,14 @@ static void perf_event_comm_output(struct perf_event *event,
{
struct perf_comm_event *comm_event = data;
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
int size = comm_event->event_id.header.size;
int ret;

if (!perf_event_comm_match(event))
return;

- perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
+ perf_event_header__init_id(&comm_event->event_id.header, psample, event);
ret = perf_output_begin(&handle, event,
comm_event->event_id.header.size);

@@ -5821,7 +5821,7 @@ static void perf_event_comm_output(struct perf_event *event,
__output_copy(&handle, comm_event->comm,
comm_event->comm_size);

- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
out:
@@ -5913,7 +5913,7 @@ static void perf_event_mmap_output(struct perf_event *event,
{
struct perf_mmap_event *mmap_event = data;
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
int size = mmap_event->event_id.header.size;
int ret;

@@ -5930,7 +5930,7 @@ static void perf_event_mmap_output(struct perf_event *event,
mmap_event->event_id.header.size += sizeof(mmap_event->flags);
}

- perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
+ perf_event_header__init_id(&mmap_event->event_id.header, psample, event);
ret = perf_output_begin(&handle, event,
mmap_event->event_id.header.size);
if (ret)
@@ -5953,7 +5953,7 @@ static void perf_event_mmap_output(struct perf_event *event,
__output_copy(&handle, mmap_event->file_name,
mmap_event->file_size);

- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
out:
@@ -6118,7 +6118,7 @@ void perf_event_aux_event(struct perf_event *event, unsigned long head,
unsigned long size, u64 flags)
{
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
struct perf_aux_event {
struct perf_event_header header;
u64 offset;
@@ -6136,14 +6136,14 @@ void perf_event_aux_event(struct perf_event *event, unsigned long head,
};
int ret;

- perf_event_header__init_id(&rec.header, &sample, event);
+ perf_event_header__init_id(&rec.header, psample, event);
ret = perf_output_begin(&handle, event, rec.header.size);

if (ret)
return;

perf_output_put(&handle, rec);
- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
}
@@ -6154,7 +6154,7 @@ void perf_event_aux_event(struct perf_event *event, unsigned long head,
void perf_log_lost_samples(struct perf_event *event, u64 lost)
{
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
int ret;

struct {
@@ -6169,7 +6169,7 @@ void perf_log_lost_samples(struct perf_event *event, u64 lost)
.lost = lost,
};

- perf_event_header__init_id(&lost_samples_event.header, &sample, event);
+ perf_event_header__init_id(&lost_samples_event.header, psample, event);

ret = perf_output_begin(&handle, event,
lost_samples_event.header.size);
@@ -6177,7 +6177,7 @@ void perf_log_lost_samples(struct perf_event *event, u64 lost)
return;

perf_output_put(&handle, lost_samples_event);
- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);
perf_output_end(&handle);
}

@@ -6205,7 +6205,7 @@ static void perf_event_switch_output(struct perf_event *event, void *data)
{
struct perf_switch_event *se = data;
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
int ret;

if (!perf_event_switch_match(event))
@@ -6224,7 +6224,7 @@ static void perf_event_switch_output(struct perf_event *event, void *data)
perf_event_tid(event, se->next_prev);
}

- perf_event_header__init_id(&se->event_id.header, &sample, event);
+ perf_event_header__init_id(&se->event_id.header, psample, event);

ret = perf_output_begin(&handle, event, se->event_id.header.size);
if (ret)
@@ -6235,7 +6235,7 @@ static void perf_event_switch_output(struct perf_event *event, void *data)
else
perf_output_put(&handle, se->event_id);

- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
}
@@ -6273,7 +6273,7 @@ static void perf_event_switch(struct task_struct *task,
static void perf_log_throttle(struct perf_event *event, int enable)
{
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
int ret;

struct {
@@ -6295,7 +6295,7 @@ static void perf_log_throttle(struct perf_event *event, int enable)
if (enable)
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;

- perf_event_header__init_id(&throttle_event.header, &sample, event);
+ perf_event_header__init_id(&throttle_event.header, psample, event);

ret = perf_output_begin(&handle, event,
throttle_event.header.size);
@@ -6303,14 +6303,14 @@ static void perf_log_throttle(struct perf_event *event, int enable)
return;

perf_output_put(&handle, throttle_event);
- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);
perf_output_end(&handle);
}

static void perf_log_itrace_start(struct perf_event *event)
{
struct perf_output_handle handle;
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
struct perf_aux_event {
struct perf_event_header header;
u32 pid;
@@ -6331,14 +6331,14 @@ static void perf_log_itrace_start(struct perf_event *event)
rec.pid = perf_event_pid(event, current);
rec.tid = perf_event_tid(event, current);

- perf_event_header__init_id(&rec.header, &sample, event);
+ perf_event_header__init_id(&rec.header, psample, event);
ret = perf_output_begin(&handle, event, rec.header.size);

if (ret)
return;

perf_output_put(&handle, rec);
- perf_event__output_id_sample(event, &handle, &sample);
+ perf_event__output_id_sample(event, &handle, psample);

perf_output_end(&handle);
}
@@ -6647,13 +6647,13 @@ inline void perf_swevent_put_recursion_context(int rctx)

void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
- struct perf_sample_data data;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(pdata, temp);

if (WARN_ON_ONCE(!regs))
return;

- perf_sample_data_init(&data, addr, 0);
- do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
+ perf_sample_data_init(pdata, addr, 0);
+ do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, pdata, regs);
}

void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
@@ -6905,7 +6905,7 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx,
struct task_struct *task)
{
- struct perf_sample_data data;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(pdata, temp);
struct perf_event *event;

struct perf_raw_record raw = {
@@ -6913,12 +6913,12 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
.data = record,
};

- perf_sample_data_init(&data, addr, 0);
- data.raw = &raw;
+ perf_sample_data_init(pdata, addr, 0);
+ pdata->raw = &raw;

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, pdata, regs))
+ perf_swevent_event(event, count, pdata, regs);
}

/*
@@ -6939,8 +6939,8 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
continue;
if (event->attr.config != entry->type)
continue;
- if (perf_tp_event_match(event, &data, regs))
- perf_swevent_event(event, count, &data, regs);
+ if (perf_tp_event_match(event, pdata, regs))
+ perf_swevent_event(event, count, pdata, regs);
}
unlock:
rcu_read_unlock();
@@ -7087,13 +7087,13 @@ static void perf_event_free_bpf_prog(struct perf_event *event)
#ifdef CONFIG_HAVE_HW_BREAKPOINT
void perf_bp_event(struct perf_event *bp, void *data)
{
- struct perf_sample_data sample;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample, temp);
struct pt_regs *regs = data;

- perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
+ perf_sample_data_init(psample, bp->attr.bp_addr, 0);

if (!bp->hw.state && !perf_exclude_event(bp, regs))
- perf_swevent_event(bp, 1, &sample, regs);
+ perf_swevent_event(bp, 1, psample, regs);
}
#endif

@@ -7104,7 +7104,7 @@ void perf_bp_event(struct perf_event *bp, void *data)
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
{
enum hrtimer_restart ret = HRTIMER_RESTART;
- struct perf_sample_data data;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(pdata, temp);
struct pt_regs *regs;
struct perf_event *event;
u64 period;
@@ -7116,12 +7116,12 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)

event->pmu->read(event);

- perf_sample_data_init(&data, 0, event->hw.last_period);
+ perf_sample_data_init(pdata, 0, event->hw.last_period);
regs = get_irq_regs();

if (regs && !perf_exclude_event(event, regs)) {
if (!(event->attr.exclude_idle && is_idle_task(current)))
- if (__perf_event_overflow(event, 1, &data, regs))
+ if (__perf_event_overflow(event, 1, pdata, regs))
ret = HRTIMER_NORESTART;
}

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 9f1a93f..2827bea 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -181,7 +181,7 @@ int perf_output_begin(struct perf_output_handle *handle,
handle->size = (1UL << page_shift) - offset;

if (unlikely(have_lost)) {
- struct perf_sample_data sample_data;
+ DEFINE_PERF_SAMPLE_DATA_ALIGNED(psample_data, temp);

lost_event.header.size = sizeof(lost_event);
lost_event.header.type = PERF_RECORD_LOST;
@@ -190,9 +190,9 @@ int perf_output_begin(struct perf_output_handle *handle,
lost_event.lost = local_xchg(&rb->lost, 0);

perf_event_header__init_id(&lost_event.header,
- &sample_data, event);
+ psample_data, event);
perf_output_put(handle, lost_event);
- perf_event__output_id_sample(event, handle, &sample_data);
+ perf_event__output_id_sample(event, handle, psample_data);
}

return 0;
--
1.8.3.4

Next message: Wenyou Yang: "[PATCH v7 0/2] power: act8945a: add charger driver for the sub-device of ACT8945A MFD"
Previous message: Alexey Kardashevskiy: "Re: [PATCH kernel] vfio: Only check for bus IOMMU when NOIOMMU is selected"
Next in thread: kbuild test robot: "Re: [PATCH] perf core: Get rid of 'uses dynamic stack allocation' warning"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]