On Fri, Oct 30, 2020 at 10:00:37AM +0100, Peter Zijlstra wrote:
> > static void __intel_pmu_pebs_event(struct perf_event *event,
> > struct pt_regs *iregs,
> > void *base, void *top,
> > int bit, int count,
> > void (*setup_sample)(struct perf_event *,
> > struct pt_regs *,
> > void *,
> > struct perf_sample_data *,
> > struct pt_regs *))
> > {
> > struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> > struct hw_perf_event *hwc = &event->hw;
> > struct perf_sample_data data;
> > struct x86_perf_regs perf_regs;
> > struct pt_regs *regs = &perf_regs.regs;
> > void *at = get_next_pebs_record_by_bit(base, top, bit);
> > struct pt_regs dummy_iregs;
>
> The only thing I can come up with in a hurry is that that dummy_iregs
> thing really should be static. That's 168 bytes of stack out the window
> right there.
---
Subject: perf/x86: Make dummy_iregs static
From: Peter Zijlstra <pet...@infradead.org>
Date: Fri Oct 30 12:15:06 CET 2020
Having pt_regs on-stack is unfortunate, it's 168 bytes. Since it isn't
actually used, make it a static variable. This both gets if off the
stack and ensures it gets 0 initialized, just in case someone does
look at it.
Reported-by: Steven Rostedt <rost...@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/x86/events/intel/ds.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1735,7 +1735,7 @@ static void __intel_pmu_pebs_event(struc
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
void *at = get_next_pebs_record_by_bit(base, top, bit);
- struct pt_regs dummy_iregs;
+ static struct pt_regs dummy_iregs;
if (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) {
/*
