linux-kernel - [PATCH 27/37] perf tools: Fix machine__create_kernel

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Date:	Thu, 19 Nov 2015 14:53:13 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 27/37] perf tools: Fix machine__create_kernel_maps to put kernel dso refcount

From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>

Fix machine__create_kernel_maps() to put kernel dso because the dso has
been gotten via __machine__create_kernel_maps().

Refcnt debugger shows:
  ==== [0] ====
  Unreclaimed dso: 0x3036ab0
  Refcount +1 => 1 at
    ./perf(dso__new+0x1ff) [0x4a62df]
    ./perf(__dsos__addnew+0x29) [0x4a6e19]
    ./perf(dsos__findnew+0xd1) [0x4a7181]
    ./perf(machine__findnew_kernel+0x27) [0x4a5e17]
    ./perf() [0x4b8cf2]
    ./perf(machine__create_kernel_maps+0x28) [0x4bb428]
    ./perf(machine__new_host+0xfa) [0x4bb74a]
    ./perf(init_probe_symbol_maps+0x93) [0x506613]
    ./perf() [0x455ffa]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7ffa6809eaf5]
    ./perf() [0x4220a9]
  [snip]
  Refcount +1 => 2 at
    ./perf(dsos__findnew+0x7e) [0x4a712e]
    ./perf(machine__findnew_kernel+0x27) [0x4a5e17]
    ./perf() [0x4b8cf2]
    ./perf(machine__create_kernel_maps+0x28) [0x4bb428]
    ./perf(machine__new_host+0xfa) [0x4bb74a]
    ./perf(init_probe_symbol_maps+0x93) [0x506613]
    ./perf() [0x455ffa]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7ffa6809eaf5]
    ./perf() [0x4220a9]
  [snip]
  Refcount -1 => 1 at
    ./perf(dso__put+0x2f) [0x4a664f]
    ./perf(machine__delete+0xfe) [0x4b93ee]
    ./perf(exit_probe_symbol_maps+0x28) [0x5066b8]
    ./perf() [0x45628a]
    ./perf(cmd_probe+0x6c) [0x4566bc]
    ./perf() [0x47abc5]
    ./perf(main+0x610) [0x421f90]
    /lib64/libc.so.6(__libc_start_main+0xf5) [0x7ffa6809eaf5]
    ./perf() [0x4220a9]

Actually, dsos__findnew gets the dso before returning it, so the dso
user (in this case machine__create_kernel_maps) has to put the dso after
used.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/r/20151118064033.30709.98954.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/machine.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index a358771fe9e3..0b4a05c14204 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1088,11 +1088,14 @@ int machine__create_kernel_maps(struct machine *machine)
 	struct dso *kernel = machine__get_kernel(machine);
 	const char *name;
 	u64 addr = machine__get_running_kernel_start(machine, &name);
-	if (!addr)
+	int ret;
+
+	if (!addr || kernel == NULL)
 		return -1;
 
-	if (kernel == NULL ||
-	    __machine__create_kernel_maps(machine, kernel) < 0)
+	ret = __machine__create_kernel_maps(machine, kernel);
+	dso__put(kernel);
+	if (ret < 0)
 		return -1;
 
 	if (symbol_conf.use_modules && machine__create_modules(machine) < 0) {
-- 
2.1.0

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