kmemleak: Protect the seq start/next/stop sequence by rcu_read_lock() (f5886c7f) · Commits · 戴 / test

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:

Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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);

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