Messages in this thread | | | Date | Tue, 14 Oct 2014 15:58:29 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v2] perf tools: fix off-by-one error in maps |
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Em Tue, Oct 07, 2014 at 05:17:12PM +0200, Stephane Eranian escreveu: > On Tue, Oct 7, 2014 at 5:10 PM, Arnaldo Carvalho de Melo > <acme@redhat.com> wrote: > > Em Tue, Oct 07, 2014 at 04:17:41PM +0200, Stephane Eranian escreveu: > >> On Tue, Oct 7, 2014 at 4:00 PM, Arnaldo Carvalho de Melo > >> >> +++ b/tools/perf/util/map.c > >> >> @@ -752,7 +752,7 @@ struct map *maps__find(struct rb_root *maps, u64 ip) > >> >> m = rb_entry(parent, struct map, rb_node); > >> >> if (ip < m->start) > >> >> p = &(*p)->rb_left; > >> >> - else if (ip > m->end) > >> >> + else if (ip >= m->end) > >> >> p = &(*p)->rb_right; > >> >> else > >> >> return m;
> >> > I keep thinking that this change is making things unclear.
> >> > I.e. the _start_ of a map (map->start) is _in_ the map, and the _end_ > >> > of a map (map->end) is _in_ the map as well.
> >> > if (addr > m->end)
> >> > is shorter than:
> >> > if (addr >= m->end)
> >> > "start" and "end" should have the same rule applied, i.e. if one is in, > >> > the other is in as well.
> >> It is okay but then we need to be consistent all across. This is not > >> the case today. > >> I mentioned the cases I ran into.
> > Ok, and provided a patch doing the way I thought was confusing, now its > > my turn to use that info and come up with a patch, ok, will do that.
> You got it! ;->
struct vm_area_struct { /* The first cache line has the info for VMA tree walking. */
unsigned long vm_start; /* Our start address within vm_mm. */ unsigned long vm_end; /* The first byte after our end address within vm_mm. */
So these guys have been doing this far longer than me, I guess I'll bow to this convention.
But by renaming map->end to map->end_ and looking at all the usage of it, there are some inconsistencies...
Like symbol->{start,end} is of the [start,end] case, and to be consistent with above needs to also move to [start,end[, will cook a patch and send for review.
- Arnaldo
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