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Commit f5886c7f authored by Catalin Marinas's avatar Catalin Marinas Committed by Linus Torvalds
Browse files

kmemleak: Protect the seq start/next/stop sequence by rcu_read_lock() 



Objects passed to kmemleak_seq_next() have an incremented reference
count (hence not freed) but they may point via object_list.next to
other freed objects. To avoid this, the whole start/next/stop sequence
must be protected by rcu_read_lock().

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 84210aeb

mm/kmemleak.c

+1 −3
Original line number Diff line number Diff line
@@ -1217,7 +1217,6 @@ static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) 
	}

	object = NULL;

out:

	rcu_read_unlock();

	return object;

}
@@ -1233,13 +1232,11 @@ static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) 


	++(*pos);



	rcu_read_lock();

	list_for_each_continue_rcu(n, &object_list) {

		next_obj = list_entry(n, struct kmemleak_object, object_list);

		if (get_object(next_obj))

			break;

	}

	rcu_read_unlock();



	put_object(prev_obj);

	return next_obj;
@@ -1255,6 +1252,7 @@ static void kmemleak_seq_stop(struct seq_file *seq, void *v) 
		 * kmemleak_seq_start may return ERR_PTR if the scan_mutex

		 * waiting was interrupted, so only release it if !IS_ERR.

		 */

		rcu_read_unlock();

		mutex_unlock(&scan_mutex);

		if (v)

			put_object(v);