perf tools: Fix __dsos__addnew to put dso after adding it to the list

__dsos__addnew should drop the constructor reference to dso after adding
it to the list, because __dsos__add() will get a reference that will be
kept while it is in the list.

This fixes DSO leaks when entries are removed to the list and the refcount
never gets to zero.

Refcnt debugger shows:
  ==== [0] ====
  Unreclaimed dso: 0x2fccab0
  Refcount +1 => 1 at
    ./perf(dso__new+0x1ff) [0x4a62df]
    ./perf(__dsos__addnew+0x29) [0x4a6e19]
    ./perf(dsos__findnew+0xd1) [0x4a7281]
    ./perf(machine__findnew_kernel+0x27) [0x4a5e17]
    ./perf() [0x4b8df2]
    ./perf(machine__create_kernel_maps+0x28) [0x4bb528]
    ./perf(machine__new_host+0xfa) [0x4bb84a]
    ./perf(init_probe_symbol_maps+0x93) [0x506713]
    ./perf() [0x455ffa]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f46df132af5]
    ./perf() [0x4220a9]
  Refcount +1 => 2 at
    ./perf(__dsos__addnew+0xfb) [0x4a6eeb]
    ./perf(dsos__findnew+0xd1) [0x4a7281]
    ./perf(machine__findnew_kernel+0x27) [0x4a5e17]
    ./perf() [0x4b8df2]
    ./perf(machine__create_kernel_maps+0x28) [0x4bb528]
    ./perf(machine__new_host+0xfa) [0x4bb84a]
    ./perf(init_probe_symbol_maps+0x93) [0x506713]
    ./perf() [0x455ffa]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f46df132af5]
    ./perf() [0x4220a9]
  Refcount +1 => 3 at
    ./perf(dsos__findnew+0x7e) [0x4a722e]
    ./perf(machine__findnew_kernel+0x27) [0x4a5e17]
    ./perf() [0x4b8df2]
    ./perf(machine__create_kernel_maps+0x28) [0x4bb528]
    ./perf(machine__new_host+0xfa) [0x4bb84a]
    ./perf(init_probe_symbol_maps+0x93) [0x506713]
    ./perf() [0x455ffa]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f46df132af5]
    ./perf() [0x4220a9]
  [snip]

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20151118064031.30709.81460.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 425df5c86c9c..e8e9a9dbf5e3 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1243,6 +1243,8 @@ struct dso *__dsos__addnew(struct dsos *dsos, const char *name)
         if (dso != NULL) {
                 __dsos__add(dsos, dso);
                 dso__set_basename(dso);
+                /* Put dso here because __dsos_add already got it */
+                dso__put(dso);
         }
         return dso;
 }