Commit 535caaca authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: annotate data-races around cleanup_net_task 



from_cleanup_net() reads cleanup_net_task locklessly.

Add READ_ONCE()/WRITE_ONCE() annotations to avoid
a potential KCSAN warning, even if the race is harmless.

Fixes: 0734d7c3 ("net: expedite synchronize_net() for cleanup_net()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20250604093928.1323333-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e6854be4

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -10499,7 +10499,7 @@ static void dev_index_release(struct net *net, int ifindex) 
static bool from_cleanup_net(void)

{

#ifdef CONFIG_NET_NS

	return current == cleanup_net_task;

	return current == READ_ONCE(cleanup_net_task);

#else

	return false;

#endif

net/core/net_namespace.c

+2 −2
Original line number Diff line number Diff line
@@ -654,7 +654,7 @@ static void cleanup_net(struct work_struct *work) 
	struct net *net, *tmp, *last;

	LIST_HEAD(net_exit_list);



	cleanup_net_task = current;

	WRITE_ONCE(cleanup_net_task, current);



	/* Atomically snapshot the list of namespaces to cleanup */

	net_kill_list = llist_del_all(&cleanup_list);
@@ -704,7 +704,7 @@ static void cleanup_net(struct work_struct *work) 
		put_user_ns(net->user_ns);

		net_passive_dec(net);

	}

	cleanup_net_task = NULL;

	WRITE_ONCE(cleanup_net_task, NULL);

}



/**