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@intel.com>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: alsa-devel@alsa-project.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1487691303-31858-2-git-send-email-elena.reshetova@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index eafbf11442b224f90ad9c5d704df75d86985f917..86399eda3684b2b1969a7d09cc3e5ebfa157cbca 100644 (file)
--- 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 31f8dcdbd7efefac48353b90715c027cf2c13386..d91966b97cbd7235f9fd756c50cd41ba7d7fadae 100644 (file)
--- 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;
 };