From: Eric Dumazet edumazet@google.com
[ Upstream commit 2d3916f3189172d5c69d33065c3c21119fe539fc ]
While investigating on why a synchronize_net() has been added recently in ipv6_mc_down(), I found that igmp6_event_query() and igmp6_event_report() might drop skbs in some cases.
Discussion about removing synchronize_net() from ipv6_mc_down() will happen in a different thread.
Fixes: f185de28d9ae ("mld: add new workqueues for process mld events") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Taehee Yoo ap420073@gmail.com Cc: Cong Wang xiyou.wangcong@gmail.com Cc: David Ahern dsahern@kernel.org Link: https://lore.kernel.org/r/20220303173728.937869-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ndisc.h | 4 ++-- net/ipv6/mcast.c | 32 ++++++++++++-------------------- 2 files changed, 14 insertions(+), 22 deletions(-)
diff --git a/include/net/ndisc.h b/include/net/ndisc.h index 04341d86585de..5e37e58586796 100644 --- a/include/net/ndisc.h +++ b/include/net/ndisc.h @@ -487,9 +487,9 @@ int igmp6_late_init(void); void igmp6_cleanup(void); void igmp6_late_cleanup(void);
-int igmp6_event_query(struct sk_buff *skb); +void igmp6_event_query(struct sk_buff *skb);
-int igmp6_event_report(struct sk_buff *skb); +void igmp6_event_report(struct sk_buff *skb);
#ifdef CONFIG_SYSCTL diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index a8861db52c187..909f937befd71 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1371,27 +1371,23 @@ static void mld_process_v2(struct inet6_dev *idev, struct mld2_query *mld, }
/* called with rcu_read_lock() */ -int igmp6_event_query(struct sk_buff *skb) +void igmp6_event_query(struct sk_buff *skb) { struct inet6_dev *idev = __in6_dev_get(skb->dev);
- if (!idev) - return -EINVAL; - - if (idev->dead) { - kfree_skb(skb); - return -ENODEV; - } + if (!idev || idev->dead) + goto out;
spin_lock_bh(&idev->mc_query_lock); if (skb_queue_len(&idev->mc_query_queue) < MLD_MAX_SKBS) { __skb_queue_tail(&idev->mc_query_queue, skb); if (!mod_delayed_work(mld_wq, &idev->mc_query_work, 0)) in6_dev_hold(idev); + skb = NULL; } spin_unlock_bh(&idev->mc_query_lock); - - return 0; +out: + kfree_skb(skb); }
static void __mld_query_work(struct sk_buff *skb) @@ -1542,27 +1538,23 @@ static void mld_query_work(struct work_struct *work) }
/* called with rcu_read_lock() */ -int igmp6_event_report(struct sk_buff *skb) +void igmp6_event_report(struct sk_buff *skb) { struct inet6_dev *idev = __in6_dev_get(skb->dev);
- if (!idev) - return -EINVAL; - - if (idev->dead) { - kfree_skb(skb); - return -ENODEV; - } + if (!idev || idev->dead) + goto out;
spin_lock_bh(&idev->mc_report_lock); if (skb_queue_len(&idev->mc_report_queue) < MLD_MAX_SKBS) { __skb_queue_tail(&idev->mc_report_queue, skb); if (!mod_delayed_work(mld_wq, &idev->mc_report_work, 0)) in6_dev_hold(idev); + skb = NULL; } spin_unlock_bh(&idev->mc_report_lock); - - return 0; +out: + kfree_skb(skb); }
static void __mld_report_work(struct sk_buff *skb)