ec764bf083
Because there is a possibility that skb is kfree_skb()ed and zero cleared after ndo_start_xmit, we should not see the contents of skb like skb->len and skb->dev->name after ndo_start_xmit. But trace_net_dev_xmit does that and causes panic by NULL pointer dereference. This patch fixes trace_net_dev_xmit not to see the contents of skb directly. If you want to reproduce this panic, 1. Get tracepoint of net_dev_xmit on 2. Create 2 guests on KVM 2. Make 2 guests use virtio_net 4. Execute netperf from one to another for a long time as a network burden 5. host will panic(It takes about 30 minutes) Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
84 lines
1.6 KiB
C
84 lines
1.6 KiB
C
#undef TRACE_SYSTEM
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#define TRACE_SYSTEM net
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#if !defined(_TRACE_NET_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_NET_H
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/ip.h>
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#include <linux/tracepoint.h>
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TRACE_EVENT(net_dev_xmit,
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TP_PROTO(struct sk_buff *skb,
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int rc,
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struct net_device *dev,
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unsigned int skb_len),
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TP_ARGS(skb, rc, dev, skb_len),
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TP_STRUCT__entry(
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__field( void *, skbaddr )
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__field( unsigned int, len )
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__field( int, rc )
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__string( name, dev->name )
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),
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TP_fast_assign(
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__entry->skbaddr = skb;
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__entry->len = skb_len;
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__entry->rc = rc;
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__assign_str(name, dev->name);
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),
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TP_printk("dev=%s skbaddr=%p len=%u rc=%d",
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__get_str(name), __entry->skbaddr, __entry->len, __entry->rc)
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);
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DECLARE_EVENT_CLASS(net_dev_template,
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TP_PROTO(struct sk_buff *skb),
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TP_ARGS(skb),
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TP_STRUCT__entry(
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__field( void *, skbaddr )
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__field( unsigned int, len )
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__string( name, skb->dev->name )
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),
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TP_fast_assign(
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__entry->skbaddr = skb;
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__entry->len = skb->len;
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__assign_str(name, skb->dev->name);
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),
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TP_printk("dev=%s skbaddr=%p len=%u",
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__get_str(name), __entry->skbaddr, __entry->len)
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)
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DEFINE_EVENT(net_dev_template, net_dev_queue,
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TP_PROTO(struct sk_buff *skb),
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TP_ARGS(skb)
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);
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DEFINE_EVENT(net_dev_template, netif_receive_skb,
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TP_PROTO(struct sk_buff *skb),
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TP_ARGS(skb)
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);
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DEFINE_EVENT(net_dev_template, netif_rx,
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TP_PROTO(struct sk_buff *skb),
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TP_ARGS(skb)
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);
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#endif /* _TRACE_NET_H */
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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