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Commit e34f5b11 authored by Elena Reshetova's avatar Elena Reshetova Committed by Arnaldo Carvalho de Melo
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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: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Kook <keescook@chromium.org>
Tested-by: default avatarArnaldo 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 25a3720c

tools/perf/util/machine.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

tools/perf/util/thread.c

+3 −3
Original line number Diff line number Diff line
@@ -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.

tools/perf/util/thread.h

+2 −2
Original line number Diff line number Diff line 
#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;