perf thread: convert thread.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: 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>
Cc: alsa-devel@alsa-project.org
Link: http://lkml.kernel.org/r/1487691303-31858-9-git-send-email-elena.reshetova@intel.com
[ Did missing conversion in __machine__remove_thread() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 71c9720..b9974fe 100644 (file)
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1439,7 +1439,7 @@ static void __machine__remove_thread(struct machine *machine, struct thread *th,
        if (machine->last_match == th)
                machine->last_match = NULL;
 
-       BUG_ON(atomic_read(&th->refcnt) == 0);
+       BUG_ON(refcount_read(&th->refcnt) == 0);
        if (lock)
                pthread_rwlock_wrlock(&machine->threads_lock);
        rb_erase_init(&th->rb_node, &machine->threads);

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index f5af87f..74e79d2 100644 (file)
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -53,7 +53,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
                        goto err_thread;
 
                list_add(&comm->list, &thread->comm_list);
-               atomic_set(&thread->refcnt, 1);
+               refcount_set(&thread->refcnt, 1);
                RB_CLEAR_NODE(&thread->rb_node);
        }
 
@@ -88,13 +88,13 @@ void thread__delete(struct thread *thread)
 struct thread *thread__get(struct thread *thread)
 {
        if (thread)
-               atomic_inc(&thread->refcnt);
+               refcount_inc(&thread->refcnt);
        return thread;
 }
 
 void thread__put(struct thread *thread)
 {
-       if (thread && atomic_dec_and_test(&thread->refcnt)) {
+       if (thread && refcount_dec_and_test(&thread->refcnt)) {
                /*
                 * Remove it from the dead_threads list, as last reference
                 * is gone.

diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 99263cb..e571885 100644 (file)
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -1,7 +1,7 @@
 #ifndef __PERF_THREAD_H
 #define __PERF_THREAD_H
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/rbtree.h>
 #include <linux/list.h>
 #include <unistd.h>
@@ -23,7 +23,7 @@ struct thread {
        pid_t                   tid;
        pid_t                   ppid;
        int                     cpu;
-       atomic_t                refcnt;
+       refcount_t              refcnt;
        char                    shortname[3];
        bool                    comm_set;
        int                     comm_len;