From 138437f591dd9a42d53c6fed1a3c85e02678851c Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Sun, 11 Jun 2017 09:44:20 +0800 Subject: xfrm: move xfrm_garbage_collect out of xfrm_policy_flush Now we will force to do garbage collection if any policy removed in xfrm_policy_flush(). But during xfrm_net_exit(). We call flow_cache_fini() first and set set fc->percpu to NULL. Then after we call xfrm_policy_fini() -> frxm_policy_flush() -> flow_cache_flush(), we will get NULL pointer dereference when check percpu_empty. The code path looks like: flow_cache_fini() - fc->percpu = NULL xfrm_policy_fini() - xfrm_policy_flush() - xfrm_garbage_collect() - flow_cache_flush() - flow_cache_percpu_empty() - fcp = per_cpu_ptr(fc->percpu, cpu) To reproduce, just add ipsec in netns and then remove the netns. v2: As Xin Long suggested, since only two other places need to call it. move xfrm_garbage_collect() outside xfrm_policy_flush(). v3: Fix subject mismatch after v2 fix. Fixes: 35db06912189 ("xfrm: do the garbage collection after flushing policy") Signed-off-by: Hangbin Liu Reviewed-by: Xin Long Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_policy.c | 4 ---- net/xfrm/xfrm_user.c | 1 + 2 files changed, 1 insertion(+), 4 deletions(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index ed4e52d95172..643a18f72032 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1006,10 +1006,6 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid) err = -ESRCH; out: spin_unlock_bh(&net->xfrm.xfrm_policy_lock); - - if (cnt) - xfrm_garbage_collect(net); - return err; } EXPORT_SYMBOL(xfrm_policy_flush); diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 38614df33ec8..86116e9aaf3d 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2027,6 +2027,7 @@ static int xfrm_flush_policy(struct sk_buff *skb, struct nlmsghdr *nlh, return 0; return err; } + xfrm_garbage_collect(net); c.data.type = type; c.event = nlh->nlmsg_type; -- cgit v1.2.3-59-g8ed1b