From 6b57ff21a3109b1dba2d286ff415463e6fb1fca3 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:15 -0800 Subject: rtnetlink: Protect link_ops by mutex. rtnl_link_unregister() holds RTNL and calls synchronize_srcu(), but rtnl_newlink() will acquire SRCU frist and then RTNL. Then, we need to unlink ops and call synchronize_srcu() outside of RTNL to avoid the deadlock. rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); Let's move as such and add a mutex to protect link_ops. Now, link_ops is protected by its dedicated mutex and rtnl_link_register() no longer needs to hold RTNL. While at it, we move the initialisation of ops->dellink and ops->srcu out of the mutex scope. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- include/net/rtnetlink.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index 3ebfcc6e56fd..7559020f760c 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -71,7 +71,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh) /** * struct rtnl_link_ops - rtnetlink link operations * - * @list: Used internally, protected by RTNL and SRCU + * @list: Used internally, protected by link_ops_mutex and SRCU * @srcu: Used internally * @kind: Identifier * @netns_refund: Physical device, move to init_net on netns exit -- cgit v1.2.3