Re: [RFC patch 25/41] mm/kasan: Simplify stacktrace handling

[Thomas Gleixner <tglx@linutronix.de>]

On Wed, 10 Apr 2019, Josh Poimboeuf wrote:
> On Wed, Apr 10, 2019 at 12:28:19PM +0200, Thomas Gleixner wrote:
> > Replace the indirection through struct stack_trace by using the storage
> > array based interfaces.
> > 
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> > Cc: Alexander Potapenko <glider@google.com>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: kasan-dev@googlegroups.com
> > Cc: linux-mm@kvack.org
> > ---
> >  mm/kasan/common.c |   30 ++++++++++++------------------
> >  mm/kasan/report.c |    7 ++++---
> >  2 files changed, 16 insertions(+), 21 deletions(-)
> > 
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -48,34 +48,28 @@ static inline int in_irqentry_text(unsig
> >  		 ptr < (unsigned long)&__softirqentry_text_end);
> >  }
> >  
> > -static inline void filter_irq_stacks(struct stack_trace *trace)
> > +static inline unsigned int filter_irq_stacks(unsigned long *entries,
> > +					     unsigned int nr_entries)
> >  {
> > -	int i;
> > +	unsigned int i;
> >  
> > -	if (!trace->nr_entries)
> > -		return;
> > -	for (i = 0; i < trace->nr_entries; i++)
> > -		if (in_irqentry_text(trace->entries[i])) {
> > +	for (i = 0; i < nr_entries; i++) {
> > +		if (in_irqentry_text(entries[i])) {
> >  			/* Include the irqentry function into the stack. */
> > -			trace->nr_entries = i + 1;
> > -			break;
> > +			return i + 1;
> 
> Isn't this an off-by-one error if "i" points to the last entry of the
> array?

Yes, copied one ...