From 707693c8a498697aa8db240b93eb76ec62e30892 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 28 Nov 2016 19:22:12 +0800 Subject: netlink: Call cb->done from a worker thread The cb->done interface expects to be called in process context. This was broken by the netlink RCU conversion. This patch fixes it by adding a worker struct to make the cb->done call where necessary. Fixes: 21e4902aea80 ("netlink: Lockless lookup with RCU grace...") Reported-by: Subash Abhinov Kasiviswanathan Signed-off-by: Herbert Xu Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 27 +++++++++++++++++++++++---- net/netlink/af_netlink.h | 2 ++ 2 files changed, 25 insertions(+), 4 deletions(-) (limited to 'net') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 62bea4591054..602e5ebe9db3 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -322,14 +322,11 @@ static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) sk_mem_charge(sk, skb->truesize); } -static void netlink_sock_destruct(struct sock *sk) +static void __netlink_sock_destruct(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); if (nlk->cb_running) { - if (nlk->cb.done) - nlk->cb.done(&nlk->cb); - module_put(nlk->cb.module); kfree_skb(nlk->cb.skb); } @@ -346,6 +343,28 @@ static void netlink_sock_destruct(struct sock *sk) WARN_ON(nlk_sk(sk)->groups); } +static void netlink_sock_destruct_work(struct work_struct *work) +{ + struct netlink_sock *nlk = container_of(work, struct netlink_sock, + work); + + nlk->cb.done(&nlk->cb); + __netlink_sock_destruct(&nlk->sk); +} + +static void netlink_sock_destruct(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (nlk->cb_running && nlk->cb.done) { + INIT_WORK(&nlk->work, netlink_sock_destruct_work); + schedule_work(&nlk->work); + return; + } + + __netlink_sock_destruct(sk); +} + /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on * SMP. Look, when several writers sleep and reader wakes them up, all but one * immediately hit write lock and grab all the cpus. Exclusive sleep solves diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index 3cfd6cc60504..4fdb38318977 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -3,6 +3,7 @@ #include #include +#include #include #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) @@ -33,6 +34,7 @@ struct netlink_sock { struct rhash_head node; struct rcu_head rcu; + struct work_struct work; }; static inline struct netlink_sock *nlk_sk(struct sock *sk) -- cgit v1.2.3