Messages in this thread | | | Date | Tue, 8 Jun 2021 09:47:54 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf session: Correct buffer copying when peek event |
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Em Tue, Jun 08, 2021 at 01:07:22PM +0200, Jiri Olsa escreveu: > On Sat, Jun 05, 2021 at 01:29:57PM +0800, Leo Yan wrote: > > When peek an event, it has a short path and a long path. The short path > > uses the session pointer "one_mmap_addr" to directly fetch event; and > > the long path needs to read out the event header and the followed event > > data from file and fill into the buffer pointer passed through the > > argument "buf". > > > > The issue is in the long path that it copies the event header and event > > data into the same destination address which pointer "buf", this means > > the event header is overwritten. We are just lucky to run into the > > short path in most cases, so we don't hit the issue in the long path. > > > > This patch adds the offset "hdr_sz" to the pointer "buf" when copying > > the event data, so that it can reserve the event header which can be > > used properly by its caller. > > > > Fixes: 5a52f33adf02 ("perf session: Add perf_session__peek_event()") > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > > --- > > tools/perf/util/session.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c > > index 106b3d60881a..e59242c361ce 100644 > > --- a/tools/perf/util/session.c > > +++ b/tools/perf/util/session.c > > @@ -1723,6 +1723,7 @@ int perf_session__peek_event(struct perf_session *session, off_t file_offset, > > if (event->header.size < hdr_sz || event->header.size > buf_sz) > > return -1; > > > > + buf += hdr_sz; > > nice ;-) > > Acked-by: Jiri Olsa <jolsa@redhat.com>
Thanks, applied.
- Arnaldo
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