This is a note to let you know that I've just added the patch titled net: neigh: don't call kfree_skb() under spin_lock_irqsave() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-neigh-don-t-call-kfree_skb-under-spin_lock_irqsave.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d5485d9dd24e1d04e5509916515260186eb1455c Mon Sep 17 00:00:00 2001 From: Yang Yingliang <yangyingliang@xxxxxxxxxx> Date: Mon, 22 Aug 2022 10:53:46 +0800 Subject: net: neigh: don't call kfree_skb() under spin_lock_irqsave() From: Yang Yingliang <yangyingliang@xxxxxxxxxx> commit d5485d9dd24e1d04e5509916515260186eb1455c upstream. It is not allowed to call kfree_skb() from hardware interrupt context or with interrupts being disabled. So add all skb to a tmp list, then free them after spin_unlock_irqrestore() at once. Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop") Suggested-by: Denis V. Lunev <den@xxxxxxxxxx> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/core/neighbour.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -282,21 +282,27 @@ static int neigh_del_timer(struct neighb static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net) { + struct sk_buff_head tmp; unsigned long flags; struct sk_buff *skb; + skb_queue_head_init(&tmp); spin_lock_irqsave(&list->lock, flags); skb = skb_peek(list); while (skb != NULL) { struct sk_buff *skb_next = skb_peek_next(skb, list); if (net == NULL || net_eq(dev_net(skb->dev), net)) { __skb_unlink(skb, list); - dev_put(skb->dev); - kfree_skb(skb); + __skb_queue_tail(&tmp, skb); } skb = skb_next; } spin_unlock_irqrestore(&list->lock, flags); + + while ((skb = __skb_dequeue(&tmp))) { + dev_put(skb->dev); + kfree_skb(skb); + } } static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev, Patches currently in stable-queue which might be from yangyingliang@xxxxxxxxxx are queue-5.10/net-neigh-don-t-call-kfree_skb-under-spin_lock_irqsave.patch