| Message ID | 20220819044724.961356-1-yangyingliang@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v2] net: neigh: don't call kfree_skb() under spin_lock_irqsave() | expand |
On 19.08.2022 06:47, 'Yang Yingliang' via den wrote: > 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") > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > --- > net/core/neighbour.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/net/core/neighbour.c b/net/core/neighbour.c > index 5b669eb80270..d21c7de1ff1a 100644 > --- a/net/core/neighbour.c > +++ b/net/core/neighbour.c > @@ -309,14 +309,17 @@ static int neigh_del_timer(struct neighbour *n) > > 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); > struct net_device *dev = skb->dev; > + > if (net == NULL || net_eq(dev_net(dev), net)) { > struct in_device *in_dev; > > @@ -328,11 +331,16 @@ static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net) > __skb_unlink(skb, list); > > dev_put(dev); > - kfree_skb(skb); > + dev_kfree_skb_irq(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, Reviewed-by: Denis V. Lunev <den@openvz.org>
On 19/08/2022 07:47, Yang Yingliang wrote: > 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") > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > --- > net/core/neighbour.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/net/core/neighbour.c b/net/core/neighbour.c > index 5b669eb80270..d21c7de1ff1a 100644 > --- a/net/core/neighbour.c > +++ b/net/core/neighbour.c > @@ -309,14 +309,17 @@ static int neigh_del_timer(struct neighbour *n) > > 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); > struct net_device *dev = skb->dev; > + > if (net == NULL || net_eq(dev_net(dev), net)) { > struct in_device *in_dev; > > @@ -328,11 +331,16 @@ static void :q (struct sk_buff_head *list, struct net *net) > __skb_unlink(skb, list); > > dev_put(dev); > - kfree_skb(skb); > + dev_kfree_skb_irq(skb); this is still doing dev_kfree_skb_irq() instead of attaching the skb to tmp, in fact tmp seems unused so the loop below does nothing > } > skb = skb_next; > } > spin_unlock_irqrestore(&list->lock, flags); > + > + while ((skb = __skb_dequeue(&tmp))) { > + dev_put(skb->dev); Also note that there's already a dev_put() above > + kfree_skb(skb); > + } > } > > static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
Hi, On 2022/8/19 20:15, Nikolay Aleksandrov wrote: > On 19/08/2022 07:47, Yang Yingliang wrote: >> 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") >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> >> --- >> net/core/neighbour.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/net/core/neighbour.c b/net/core/neighbour.c >> index 5b669eb80270..d21c7de1ff1a 100644 >> --- a/net/core/neighbour.c >> +++ b/net/core/neighbour.c >> @@ -309,14 +309,17 @@ static int neigh_del_timer(struct neighbour *n) >> >> 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); >> struct net_device *dev = skb->dev; >> + >> if (net == NULL || net_eq(dev_net(dev), net)) { >> struct in_device *in_dev; >> >> @@ -328,11 +331,16 @@ static void :q > (struct sk_buff_head *list, struct net *net) >> __skb_unlink(skb, list); >> >> dev_put(dev); >> - kfree_skb(skb); >> + dev_kfree_skb_irq(skb); > this is still doing dev_kfree_skb_irq() instead of attaching the skb to tmp, in fact > tmp seems unused so the loop below does nothing > >> } >> skb = skb_next; >> } >> spin_unlock_irqrestore(&list->lock, flags); >> + >> + while ((skb = __skb_dequeue(&tmp))) { >> + dev_put(skb->dev); > Also note that there's already a dev_put() above I made a mistake and send a wrong patch, please ignore this patch. Thanks, Yang > >> + kfree_skb(skb); >> + } >> } >> >> static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev, > > .
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 5b669eb80270..d21c7de1ff1a 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -309,14 +309,17 @@ static int neigh_del_timer(struct neighbour *n) 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); struct net_device *dev = skb->dev; + if (net == NULL || net_eq(dev_net(dev), net)) { struct in_device *in_dev; @@ -328,11 +331,16 @@ static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net) __skb_unlink(skb, list); dev_put(dev); - kfree_skb(skb); + dev_kfree_skb_irq(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,
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") Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/core/neighbour.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)