> Em Thu, Jan 18, 2018 at 01:26:17PM -0800, [email protected] escreveu: > > From: Kan Liang <[email protected]> > > > > In perf_mmap__push(), the 'size' need to be recalculated, otherwise > > the invalid data might be pushed to the record in overwrite mode. > > > > The issue is introduced by commit 7fb4b407a124 ("perf mmap: Don't > > discard prev in backward mode"). > > In these cases, please add the Fixes tag, like: > > Fixes: 7fb4b407a124 ("perf mmap: Don't discard prev in backward mode") > > I'm doing it this time. >
Thanks. I'll be careful next time. Thanks, Kan > Thanks, > > - Arnaldo > > > When the ringbuffer is full in overwrite mode, backward_rb_find_range > > will be called to recalculate the 'start' and 'end'. The 'size' needs > > to be recalculated accordingly. > > > > Unconditionally recalculate the 'size', not just for full ringbuffer > > in overwrite mode. Because, > > - There is no harmful to recalculate the 'size' for other cases. > > - The code of calculating 'start' and 'end' will be factored out later. > > The new function does not need to return 'size'. > > > > Signed-off-by: Kan Liang <[email protected]> > > --- > > tools/perf/util/mmap.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index > > 05076e6..97cf4fa 100644 > > --- a/tools/perf/util/mmap.c > > +++ b/tools/perf/util/mmap.c > > @@ -302,6 +302,8 @@ int perf_mmap__push(struct perf_mmap *md, > bool overwrite, > > return -1; > > } > > > > + size = end - start; > > + > > if ((start & md->mask) + size != (end & md->mask)) { > > buf = &data[start & md->mask]; > > size = md->mask + 1 - (start & md->mask); > > -- > > 2.5.5
