From: Tom Rix <trix@redhat.com>
To: steffen.klassert@secunet.com, herbert@gondor.apana.org.au,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] xfrm : lock input tasklet skb queue
Date: Sun, 20 Oct 2019 08:46:10 -0700 [thread overview]
Message-ID: <CACVy4SVuw0Qbjiv6PLRn1symoxGzyBMZx2F5O23+jGZG6WHuYA@mail.gmail.com> (raw)
On PREEMPT_RT_FULL while running netperf, a corruption
of the skb queue causes an oops.
This appears to be caused by a race condition here
__skb_queue_tail(&trans->queue, skb);
tasklet_schedule(&trans->tasklet);
Where the queue is changed before the tasklet is locked by
tasklet_schedule.
The fix is to use the skb queue lock.
Signed-off-by: Tom Rix <trix@redhat.com>
---
net/xfrm/xfrm_input.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 9b599ed66d97..226dead86828 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -758,12 +758,16 @@ static void xfrm_trans_reinject(unsigned long data)
struct xfrm_trans_tasklet *trans = (void *)data;
struct sk_buff_head queue;
struct sk_buff *skb;
+ unsigned long flags;
__skb_queue_head_init(&queue);
+ spin_lock_irqsave(&trans->queue.lock, flags);
skb_queue_splice_init(&trans->queue, &queue);
while ((skb = __skb_dequeue(&queue)))
XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb);
+
+ spin_unlock_irqrestore(&trans->queue.lock, flags);
}
int xfrm_trans_queue(struct sk_buff *skb,
@@ -771,15 +775,20 @@ int xfrm_trans_queue(struct sk_buff *skb,
struct sk_buff *))
{
struct xfrm_trans_tasklet *trans;
+ unsigned long flags;
trans = this_cpu_ptr(&xfrm_trans_tasklet);
+ spin_lock_irqsave(&trans->queue.lock, flags);
- if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
+ if (skb_queue_len(&trans->queue) >= netdev_max_backlog) {
+ spin_unlock_irqrestore(&trans->queue.lock, flags);
return -ENOBUFS;
+ }
XFRM_TRANS_SKB_CB(skb)->finish = finish;
__skb_queue_tail(&trans->queue, skb);
tasklet_schedule(&trans->tasklet);
+ spin_unlock_irqrestore(&trans->queue.lock, flags);
return 0;
}
EXPORT_SYMBOL(xfrm_trans_queue);
--
2.23.0
next reply other threads:[~2019-10-20 15:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-20 15:46 Tom Rix [this message]
2019-10-21 8:37 ` [PATCH] xfrm : lock input tasklet skb queue Steffen Klassert
2019-10-21 16:31 ` Tom Rix
2019-10-22 6:12 ` Herbert Xu
2019-10-22 8:58 ` Joerg Vehlow
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