From: Eric Dumazet edumazet@google.com
[ Upstream commit cbe08724c18078564abefbf6591078a7c98e5e0f ]
Add READ_ONCE() around reads of skb->dev->reg_state, because this field can be changed from other threads/cpus.
Instead of calling dev_kfree_skb_irq() and kfree_skb() while interrupts are masked and locks held, use a temporary list and use __skb_queue_purge_reason()
Use SKB_DROP_REASON_DEV_READY drop reason to better describe why these skbs are dropped.
Signed-off-by: Eric Dumazet edumazet@google.com Reviewed-by: Jason Xing kerneljasonxing@gmail.com Link: https://patch.msgid.link/20250204144825.316785-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/dev.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c index 7b7b36c43c82c..2ba2160dd093a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6034,16 +6034,18 @@ static DEFINE_PER_CPU(struct work_struct, flush_works); static void flush_backlog(struct work_struct *work) { struct sk_buff *skb, *tmp; + struct sk_buff_head list; struct softnet_data *sd;
+ __skb_queue_head_init(&list); local_bh_disable(); sd = this_cpu_ptr(&softnet_data);
backlog_lock_irq_disable(sd); skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) { - if (skb->dev->reg_state == NETREG_UNREGISTERING) { + if (READ_ONCE(skb->dev->reg_state) == NETREG_UNREGISTERING) { __skb_unlink(skb, &sd->input_pkt_queue); - dev_kfree_skb_irq(skb); + __skb_queue_tail(&list, skb); rps_input_queue_head_incr(sd); } } @@ -6051,14 +6053,16 @@ static void flush_backlog(struct work_struct *work)
local_lock_nested_bh(&softnet_data.process_queue_bh_lock); skb_queue_walk_safe(&sd->process_queue, skb, tmp) { - if (skb->dev->reg_state == NETREG_UNREGISTERING) { + if (READ_ONCE(skb->dev->reg_state) == NETREG_UNREGISTERING) { __skb_unlink(skb, &sd->process_queue); - kfree_skb(skb); + __skb_queue_tail(&list, skb); rps_input_queue_head_incr(sd); } } local_unlock_nested_bh(&softnet_data.process_queue_bh_lock); local_bh_enable(); + + __skb_queue_purge_reason(&list, SKB_DROP_REASON_DEV_READY); }
static bool flush_required(int cpu)