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...@intel.com> Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: pi3or...@163.com --- 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