perf session: Fix perf_session__peek_event()
authorAdrian Hunter <adrian.hunter@intel.com>
Tue, 19 May 2015 13:05:45 +0000 (16:05 +0300)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Wed, 27 May 2015 15:21:43 +0000 (12:21 -0300)
commit554e92ed8fcdbcad736ef906c393847d44d52692
treea614aa7e175aad3f5e36540e03bbd7e9c1df5dcd
parent05b41775e2edd69a83f592e3534930c934d4038e
perf session: Fix perf_session__peek_event()

perf_session__peek_event() generally leverages there being a single mmap
of the perf.data file, however on 32-bit platforms when there is more
that 32MiB of data, then there are multiple mmaps, so
perf_session__peek_event() reads from the file.

In that case a couple of bugs were exposed (note how the seg. fault
appears with >32M of data):

   $ perf record --per-thread -e intel_bts// ../rtit-tests/loopy 1000000
   [ perf record: Woken up 13 times to write data ]
   [ perf record: Captured and wrote 24.568 MB perf.data ]
   $ perf script > /dev/null
   $ perf record --per-thread -e intel_bts// ../rtit-tests/loopy 10000000
   [ perf record: Woken up 136 times to write data ]
   [ perf record: Captured and wrote 270.794 MB perf.data ]
   $ perf script > /dev/null
   Segmentation fault (core dumped)

The wrong address was being passed to the readn() function and the
buffer size was not being checked.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/1432040746-1755-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/util/session.c