[tip:perf/core] perf cgroup: Convert cgroup_sel.refcnt from atomic_t to refcount_t

From: tip-bot for Elena Reshetova
Date: Tue Mar 07 2017 - 03:59:45 EST


Commit-ID: 79c5fe6db8c70558d3a64959f55596d137ccc6e6
Gitweb: http://git.kernel.org/tip/79c5fe6db8c70558d3a64959f55596d137ccc6e6
Author: Elena Reshetova <elena.reshetova@xxxxxxxxx>
AuthorDate: Tue, 21 Feb 2017 17:34:55 +0200
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 3 Mar 2017 19:07:14 -0300

perf cgroup: Convert cgroup_sel.refcnt from atomic_t to refcount_t

The refcount_t type and corresponding API should be used instead of
atomic_t when the variable is used as a reference counter.

This allows to avoid accidental refcounter overflows that might lead to
use-after-free situations.

Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Kook <keescook@xxxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Windsor <dwindsor@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kees Kook <keescook@xxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1487691303-31858-2-git-send-email-elena.reshetova@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/cgroup.c | 6 +++---
tools/perf/util/cgroup.h | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index eafbf114..86399ed 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -127,19 +127,19 @@ static int add_cgroup(struct perf_evlist *evlist, char *str)
goto found;
n++;
}
- if (atomic_read(&cgrp->refcnt) == 0)
+ if (refcount_read(&cgrp->refcnt) == 0)
free(cgrp);

return -1;
found:
- atomic_inc(&cgrp->refcnt);
+ refcount_inc(&cgrp->refcnt);
counter->cgrp = cgrp;
return 0;
}

void close_cgroup(struct cgroup_sel *cgrp)
{
- if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
+ if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
close(cgrp->fd);
zfree(&cgrp->name);
free(cgrp);
diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h
index 31f8dcd..d91966b 100644
--- a/tools/perf/util/cgroup.h
+++ b/tools/perf/util/cgroup.h
@@ -1,14 +1,14 @@
#ifndef __CGROUP_H__
#define __CGROUP_H__

-#include <linux/atomic.h>
+#include <linux/refcount.h>

struct option;

struct cgroup_sel {
char *name;
int fd;
- atomic_t refcnt;
+ refcount_t refcnt;
};