net: pass receive socket to drop tracepoint

PATCH Applied Yan Zhai 3 participants 16 messages Jun 17, 2024 – Jun 19, 2024

Subsystems (7)

Networking Network drivers Tracing TCP +3 more subsystems

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Yan Zhai

author

2024-06-17 18:09 UTC #0 lore raw

v5 cover net: pass receive socket to drop tracepoint

We set up our production packet drop monitoring around the kfree_skb tracepoint. While this tracepoint is extremely valuable for diagnosing critical problems, it also has some limitation with drops on the local receive path: this tracepoint can only inspect the dropped skb itself, but such skb might not carry enough information to:

1. determine in which netns/container this skb gets dropped
2. determine by which socket/service this skb oughts to be received

The 1st issue is because skb->dev is the only member field with valid netns reference. But skb->dev can get cleared or reused. For example, tcp_v4_rcv will clear skb->dev and in later processing it might be reused for OFO tree.

The 2nd issue is because there is no reference on an skb that reliably points to a receiving socket. skb->sk usually points to the local sending socket, and it only points to a receive socket briefly after early demux stage, yet the socket can get stolen later. For certain drop reason like TCP OFO_MERGE, Zerowindow, UDP at PROTO_MEM error, etc, it is hard to infer which receiving socket is impacted. This cannot be overcome by simply looking at the packet header, because of complications like sk lookup programs. In the past, single purpose tracepoints like trace_udp_fail_queue_rcv_skb, trace_sock_rcvqueue_full, etc are added as needed to provide more visibility. This could be handled in a more generic way.

In this change set we propose a new 'sk_skb_reason_drop' call as a drop-in replacement for kfree_skb_reason at various local input path. It accepts an extra receiving socket argument. Both issues above can be resolved via this new argument.

V4->V5: rename rx_skaddr to rx_sk to be more clear visually, suggested by Jesper Dangaard Brouer.

V3->V4: adjusted the TP_STRUCT field order to align better, suggested by Steven Rostedt.

V2->V3: fixed drop_monitor function signatures; fixed a few uninitialized sks; Added a few missing report tags from test bots (also noticed by Dan Carpenter and Simon Horman).

V1->V2: instead of using skb->cb, directly add the needed argument to trace_kfree_skb tracepoint. Also renamed functions as Eric Dumazet suggested.

V4: https://lore.kernel.org/netdev/[email protected]/
V3: https://lore.kernel.org/netdev/[email protected]/
V2: https://lore.kernel.org/linux-kernel/[email protected]/
V1: https://lore.kernel.org/netdev/[email protected]/

Yan Zhai (7):
net: add rx_sk to trace_kfree_skb
net: introduce sk_skb_reason_drop function
ping: use sk_skb_reason_drop to free rx packets
net: raw: use sk_skb_reason_drop to free rx packets
tcp: use sk_skb_reason_drop to free rx packets
udp: use sk_skb_reason_drop to free rx packets
af_packet: use sk_skb_reason_drop to free rx packets

 include/linux/skbuff.h     | 10 ++++++++--
 include/trace/events/skb.h | 11 +++++++----
 net/core/dev.c             |  2 +-
 net/core/drop_monitor.c    |  9 ++++++---
 net/core/skbuff.c          | 22 ++++++++++++----------
 net/ipv4/ping.c            |  2 +-
 net/ipv4/raw.c             |  4 ++--
 net/ipv4/syncookies.c      |  2 +-
 net/ipv4/tcp_input.c       |  2 +-
 net/ipv4/tcp_ipv4.c        |  6 +++---
 net/ipv4/udp.c             | 10 +++++-----
 net/ipv6/raw.c             |  8 ++++----
 net/ipv6/syncookies.c      |  2 +-
 net/ipv6/tcp_ipv6.c        |  6 +++---
 net/ipv6/udp.c             | 10 +++++-----
 net/packet/af_packet.c     | 10 +++++-----
 16 files changed, 65 insertions(+), 51 deletions(-)

Signature · 1 line

2.30.2

Yan Zhai

author

2024-06-17 18:09 UTC #1 lore raw

PATCH v5 1/7 net: add rx_sk to trace_kfree_skb

skb does not include enough information to find out receiving sockets/services and netns/containers on packet drops. In theory skb->dev tells about netns, but it can get cleared/reused, e.g. by TCP stack for OOO packet lookup. Similarly, skb->sk often identifies a local sender, and tells nothing about a receiver.

Allow passing an extra receiving socket to the tracepoint to improve the visibility on receiving drops.

Signed-off-by Yan Zhai <[email protected]>

---
v4->v5: rename rx_skaddr -> rx_sk as Jesper Dangaard Brouer suggested v3->v4: adjusted the TP_STRUCT field order to be consistent v2->v3: fixed drop_monitor function prototype

---
 include/trace/events/skb.h | 11 +++++++----
 net/core/dev.c             |  2 +-
 net/core/drop_monitor.c    |  9 ++++++---
 net/core/skbuff.c          |  2 +-
 4 files changed, 15 insertions(+), 9 deletions(-)

include/trace/events/skb.h +7 -4

index 07e0715628ec..b877133cd93a 100644
@@ -24,13 +24,14 @@ DEFINE_DROP_REASON(FN, FN)
 TRACE_EVENT(kfree_skb,
 
 	TP_PROTO(struct sk_buff *skb, void *location,
-		 enum skb_drop_reason reason),
+		 enum skb_drop_reason reason, struct sock *rx_sk),
 
-	TP_ARGS(skb, location, reason),
+	TP_ARGS(skb, location, reason, rx_sk),
 
 	TP_STRUCT__entry(
 		__field(void *,		skbaddr)
 		__field(void *,		location)
+		__field(void *,		rx_sk)
 		__field(unsigned short,	protocol)
 		__field(enum skb_drop_reason,	reason)
 	),

@@ -38,12 +39,14 @@ TRACE_EVENT(kfree_skb,
 	TP_fast_assign(
 		__entry->skbaddr = skb;
 		__entry->location = location;
+		__entry->rx_sk = rx_sk;
 		__entry->protocol = ntohs(skb->protocol);
 		__entry->reason = reason;
 	),
 
-	TP_printk("skbaddr=%p protocol=%u location=%pS reason: %s",
-		  __entry->skbaddr, __entry->protocol, __entry->location,
+	TP_printk("skbaddr=%p rx_sk=%p protocol=%u location=%pS reason: %s",
+		  __entry->skbaddr, __entry->rx_sk, __entry->protocol,
+		  __entry->location,
 		  __print_symbolic(__entry->reason,
 				   DEFINE_DROP_REASON(FN, FNe)))
 );

net/core/dev.c +1 -1

index 85fe8138f3e4..7844227ecbfd 100644
@@ -5233,7 +5233,7 @@ static __latent_entropy void net_tx_action(struct softirq_action *h)
 				trace_consume_skb(skb, net_tx_action);
 			else
 				trace_kfree_skb(skb, net_tx_action,
-						get_kfree_skb_cb(skb)->reason);
+						get_kfree_skb_cb(skb)->reason, NULL);
 
 			if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
 				__kfree_skb(skb);

net/core/drop_monitor.c +6 -3

index 430ed18f8584..2e0ae3328232 100644
@@ -109,7 +109,8 @@ static u32 net_dm_queue_len = 1000;
 struct net_dm_alert_ops {
 	void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
 				void *location,
-				enum skb_drop_reason reason);
+				enum skb_drop_reason reason,
+				struct sock *rx_sk);
 	void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 				int work, int budget);
 	void (*work_item_func)(struct work_struct *work);

@@ -264,7 +265,8 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
 
 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
 				void *location,
-				enum skb_drop_reason reason)
+				enum skb_drop_reason reason,
+				struct sock *rx_sk)
 {
 	trace_drop_common(skb, location);
 }

@@ -491,7 +493,8 @@ static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 					      struct sk_buff *skb,
 					      void *location,
-					      enum skb_drop_reason reason)
+					      enum skb_drop_reason reason,
+					      struct sock *rx_sk)
 {
 	ktime_t tstamp = ktime_get_real();
 	struct per_cpu_dm_data *data;

net/core/skbuff.c +1 -1

index 466999a7515e..2854afdd713f 100644
@@ -1203,7 +1203,7 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
 	if (reason == SKB_CONSUMED)
 		trace_consume_skb(skb, __builtin_return_address(0));
 	else
-		trace_kfree_skb(skb, __builtin_return_address(0), reason);
+		trace_kfree_skb(skb, __builtin_return_address(0), reason, NULL);
 	return true;
 }

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 1/7

2024-06-18 06:15 UTC #2 lore raw

Re: [PATCH net-next v5 1/7] net: add rx_sk to trace_kfree_skb

Quoted 14 lines · Yan Zhai

skb does not include enough information to find out receiving sockets/services and netns/containers on packet drops. In theory skb->dev tells about netns, but it can get cleared/reused, e.g. by TCP stack for OOO packet lookup. Similarly, skb->sk often identifies a local sender, and tells nothing about a receiver.
Allow passing an extra receiving socket to the tracepoint to improve the visibility on receiving drops.
Signed-off-by Yan Zhai<[email protected]>
---
v4->v5: rename rx_skaddr -> rx_sk as Jesper Dangaard Brouer suggested v3->v4: adjusted the TP_STRUCT field order to be consistent v2->v3: fixed drop_monitor function prototype

Quoted 6 lines

---
  include/trace/events/skb.h | 11 +++++++----
  net/core/dev.c             |  2 +-
  net/core/drop_monitor.c    |  9 ++++++---
  net/core/skbuff.c          |  2 +-
  4 files changed, 15 insertions(+), 9 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #3 lore raw

PATCH v5 2/7 net: introduce sk_skb_reason_drop function

In reply to Yan Zhai

Long used destructors kfree_skb and kfree_skb_reason do not pass receiving socket to packet drop tracepoints trace_kfree_skb. This makes it hard to track packet drops of a certain netns (container) or a socket (user application).

The naming of these destructors are also not consistent with most sk/skb operating functions, i.e. functions named "sk_xxx" or "skb_xxx". Introduce a new functions sk_skb_reason_drop as drop-in replacement for kfree_skb_reason on local receiving path. Callers can now pass receiving sockets to the tracepoints.

kfree_skb and kfree_skb_reason are still usable but they are now just inline helpers that call sk_skb_reason_drop.

Note it is not feasible to do the same to consume_skb. Packets not dropped can flow through multiple receive handlers, and have multiple receiving sockets. Leave it untouched for now.

Signed-off-by Yan Zhai <[email protected]>

---
v1->v2: changes function names to be more consistent with common sk/skb operations

---
 include/linux/skbuff.h | 10 ++++++++--
 net/core/skbuff.c      | 22 ++++++++++++----------
 2 files changed, 20 insertions(+), 12 deletions(-)

include/linux/skbuff.h +8 -2

index fe7d8dbef77e..c479a2515a62 100644
@@ -1251,8 +1251,14 @@ static inline bool skb_data_unref(const struct sk_buff *skb,
 	return true;
 }
 
-void __fix_address
-kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason);
+void __fix_address sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb,
+				      enum skb_drop_reason reason);
+
+static inline void
+kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
+{
+	sk_skb_reason_drop(NULL, skb, reason);
+}
 
 /**
  *	kfree_skb - free an sk_buff with 'NOT_SPECIFIED' reason

net/core/skbuff.c +12 ~~-10~~

index 2854afdd713f..9def11fe42c4 100644
@@ -1190,7 +1190,8 @@ void __kfree_skb(struct sk_buff *skb)
 EXPORT_SYMBOL(__kfree_skb);
 
 static __always_inline
-bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
+bool __sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb,
+			  enum skb_drop_reason reason)
 {
 	if (unlikely(!skb_unref(skb)))
 		return false;

@@ -1203,26 +1204,27 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
 	if (reason == SKB_CONSUMED)
 		trace_consume_skb(skb, __builtin_return_address(0));
 	else
-		trace_kfree_skb(skb, __builtin_return_address(0), reason, NULL);
+		trace_kfree_skb(skb, __builtin_return_address(0), reason, sk);
 	return true;
 }
 
 /**
- *	kfree_skb_reason - free an sk_buff with special reason
+ *	sk_skb_reason_drop - free an sk_buff with special reason
+ *	@sk: the socket to receive @skb, or NULL if not applicable
  *	@skb: buffer to free
  *	@reason: reason why this skb is dropped
  *
- *	Drop a reference to the buffer and free it if the usage count has
- *	hit zero. Meanwhile, pass the drop reason to 'kfree_skb'
- *	tracepoint.
+ *	Drop a reference to the buffer and free it if the usage count has hit
+ *	zero. Meanwhile, pass the receiving socket and drop reason to
+ *	'kfree_skb' tracepoint.
  */
 void __fix_address
-kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
+sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb, enum skb_drop_reason reason)
 {
-	if (__kfree_skb_reason(skb, reason))
+	if (__sk_skb_reason_drop(sk, skb, reason))
 		__kfree_skb(skb);
 }
-EXPORT_SYMBOL(kfree_skb_reason);
+EXPORT_SYMBOL(sk_skb_reason_drop);
 
 #define KFREE_SKB_BULK_SIZE	16

@@ -1261,7 +1263,7 @@ kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason)
 	while (segs) {
 		struct sk_buff *next = segs->next;
 
-		if (__kfree_skb_reason(segs, reason)) {
+		if (__sk_skb_reason_drop(NULL, segs, reason)) {
 			skb_poison_list(segs);
 			kfree_skb_add_bulk(segs, &sa, reason);
 		}

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 2/7

2024-06-18 06:18 UTC #4 lore raw

Re: [PATCH net-next v5 2/7] net: introduce sk_skb_reason_drop function

Quoted 20 lines · Yan Zhai

Long used destructors kfree_skb and kfree_skb_reason do not pass receiving socket to packet drop tracepoints trace_kfree_skb. This makes it hard to track packet drops of a certain netns (container) or a socket (user application).
The naming of these destructors are also not consistent with most sk/skb operating functions, i.e. functions named "sk_xxx" or "skb_xxx". Introduce a new functions sk_skb_reason_drop as drop-in replacement for kfree_skb_reason on local receiving path. Callers can now pass receiving sockets to the tracepoints.
kfree_skb and kfree_skb_reason are still usable but they are now just inline helpers that call sk_skb_reason_drop.
Note it is not feasible to do the same to consume_skb. Packets not dropped can flow through multiple receive handlers, and have multiple receiving sockets. Leave it untouched for now.
Suggested-by Eric Dumazet<[email protected]>
Signed-off-by Yan Zhai<[email protected]>

Quoted 7 lines

---
v1->v2: changes function names to be more consistent with common sk/skb operations
---
  include/linux/skbuff.h | 10 ++++++++--
  net/core/skbuff.c      | 22 ++++++++++++----------
  2 files changed, 20 insertions(+), 12 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #5 lore raw

PATCH v5 3/7 ping: use sk_skb_reason_drop to free rx packets

In reply to Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.

Signed-off-by Yan Zhai <[email protected]>

---
 net/ipv4/ping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

net/ipv4/ping.c +1 -1

index 823306487a82..619ddc087957 100644
@@ -946,7 +946,7 @@ static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
 	pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 		 inet_sk(sk), inet_sk(sk)->inet_num, skb);
 	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
-		kfree_skb_reason(skb, reason);
+		sk_skb_reason_drop(sk, skb, reason);
 		pr_debug("ping_queue_rcv_skb -> failed\n");
 		return reason;
 	}

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 3/7

2024-06-18 06:18 UTC #6 lore raw

Re: [PATCH net-next v5 3/7] ping: use sk_skb_reason_drop to free rx packets

Quoted 7 lines · Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.
Signed-off-by Yan Zhai<[email protected]>
---
  net/ipv4/ping.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #7 lore raw

PATCH v5 4/7 net: raw: use sk_skb_reason_drop to free rx packets

In reply to Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.

Signed-off-by Yan Zhai <[email protected]>

---
 net/ipv4/raw.c | 4 ++--
 net/ipv6/raw.c | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

net/ipv4/raw.c +2 -2

index 1a0953650356..474dfd263c8b 100644
@@ -301,7 +301,7 @@ static int raw_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 	ipv4_pktinfo_prepare(sk, skb, true);
 	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
-		kfree_skb_reason(skb, reason);
+		sk_skb_reason_drop(sk, skb, reason);
 		return NET_RX_DROP;
 	}

@@ -312,7 +312,7 @@ int raw_rcv(struct sock *sk, struct sk_buff *skb)
 {
 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
 		atomic_inc(&sk->sk_drops);
-		kfree_skb_reason(skb, SKB_DROP_REASON_XFRM_POLICY);
+		sk_skb_reason_drop(sk, skb, SKB_DROP_REASON_XFRM_POLICY);
 		return NET_RX_DROP;
 	}
 	nf_reset_ct(skb);

net/ipv6/raw.c +4 -4

index f838366e8256..608fa9d05b55 100644
@@ -362,14 +362,14 @@ static inline int rawv6_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	if ((raw6_sk(sk)->checksum || rcu_access_pointer(sk->sk_filter)) &&
 	    skb_checksum_complete(skb)) {
 		atomic_inc(&sk->sk_drops);
-		kfree_skb_reason(skb, SKB_DROP_REASON_SKB_CSUM);
+		sk_skb_reason_drop(sk, skb, SKB_DROP_REASON_SKB_CSUM);
 		return NET_RX_DROP;
 	}
 
 	/* Charge it to the socket. */
 	skb_dst_drop(skb);
 	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
-		kfree_skb_reason(skb, reason);
+		sk_skb_reason_drop(sk, skb, reason);
 		return NET_RX_DROP;
 	}

@@ -390,7 +390,7 @@ int rawv6_rcv(struct sock *sk, struct sk_buff *skb)
 
 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
 		atomic_inc(&sk->sk_drops);
-		kfree_skb_reason(skb, SKB_DROP_REASON_XFRM_POLICY);
+		sk_skb_reason_drop(sk, skb, SKB_DROP_REASON_XFRM_POLICY);
 		return NET_RX_DROP;
 	}
 	nf_reset_ct(skb);

@@ -415,7 +415,7 @@ int rawv6_rcv(struct sock *sk, struct sk_buff *skb)
 	if (inet_test_bit(HDRINCL, sk)) {
 		if (skb_checksum_complete(skb)) {
 			atomic_inc(&sk->sk_drops);
-			kfree_skb_reason(skb, SKB_DROP_REASON_SKB_CSUM);
+			sk_skb_reason_drop(sk, skb, SKB_DROP_REASON_SKB_CSUM);
 			return NET_RX_DROP;
 		}
 	}

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 4/7

2024-06-18 06:19 UTC #8 lore raw

Re: [PATCH net-next v5 4/7] net: raw: use sk_skb_reason_drop to free rx packets

Quoted 8 lines · Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.
Signed-off-by Yan Zhai<[email protected]>
---
  net/ipv4/raw.c | 4 ++--
  net/ipv6/raw.c | 8 ++++----
  2 files changed, 6 insertions(+), 6 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #9 lore raw

PATCH v5 5/7 tcp: use sk_skb_reason_drop to free rx packets

In reply to Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.

Reported-by kernel test robot <[email protected]>

Closes https://lore.kernel.org/r/[email protected]/ open here

Signed-off-by Yan Zhai <[email protected]>

---
v2->v3: added missing report tags

---
 net/ipv4/syncookies.c | 2 +-
 net/ipv4/tcp_input.c  | 2 +-
 net/ipv4/tcp_ipv4.c   | 6 +++---
 net/ipv6/syncookies.c | 2 +-
 net/ipv6/tcp_ipv6.c   | 6 +++---
 5 files changed, 9 insertions(+), 9 deletions(-)

net/ipv4/syncookies.c +1 -1

index b61d36810fe3..1948d15f1f28 100644
@@ -496,6 +496,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 out_free:
 	reqsk_free(req);
 out_drop:
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	return NULL;
 }

net/ipv4/tcp_input.c +1 -1

index 5aadf64e554d..bedb079de1f0 100644
@@ -4859,7 +4859,7 @@ static void tcp_drop_reason(struct sock *sk, struct sk_buff *skb,
 			    enum skb_drop_reason reason)
 {
 	sk_drops_add(sk, skb);
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 }
 
 /* This one checks to see if we can put data from the

net/ipv4/tcp_ipv4.c +3 -3

index 041c7eda9abe..f7a046bc4b27 100644
@@ -1939,7 +1939,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 reset:
 	tcp_v4_send_reset(rsk, skb, sk_rst_convert_drop_reason(reason));
 discard:
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	/* Be careful here. If this function gets more complicated and
 	 * gcc suffers from register pressure on the x86, sk (in %ebx)
 	 * might be destroyed here. This current version compiles correctly,

@@ -2176,8 +2176,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
 	int dif = inet_iif(skb);
 	const struct iphdr *iph;
 	const struct tcphdr *th;
+	struct sock *sk = NULL;
 	bool refcounted;
-	struct sock *sk;
 	int ret;
 	u32 isn;

@@ -2376,7 +2376,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
 discard_it:
 	SKB_DR_OR(drop_reason, NOT_SPECIFIED);
 	/* Discard frame. */
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 
 discard_and_relse:

net/ipv6/syncookies.c +1 -1

index bfad1e89b6a6..9d83eadd308b 100644
@@ -275,6 +275,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 out_free:
 	reqsk_free(req);
 out_drop:
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	return NULL;
 }

net/ipv6/tcp_ipv6.c +3 -3

index 1ac7502e1bf5..93967accc35d 100644
@@ -1678,7 +1678,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 discard:
 	if (opt_skb)
 		__kfree_skb(opt_skb);
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	return 0;
 csum_err:
 	reason = SKB_DROP_REASON_TCP_CSUM;

@@ -1751,8 +1751,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 	int dif = inet6_iif(skb);
 	const struct tcphdr *th;
 	const struct ipv6hdr *hdr;
+	struct sock *sk = NULL;
 	bool refcounted;
-	struct sock *sk;
 	int ret;
 	u32 isn;
 	struct net *net = dev_net(skb->dev);

@@ -1944,7 +1944,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 
 discard_it:
 	SKB_DR_OR(drop_reason, NOT_SPECIFIED);
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 
 discard_and_relse:

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 5/7

2024-06-18 06:21 UTC #10 lore raw

Re: [PATCH net-next v5 5/7] tcp: use sk_skb_reason_drop to free rx packets

Quoted 8 lines · Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.
Reported-by kernel test robot<[email protected]>
Closes https://lore.kernel.org/r/[email protected]/ open here
Signed-off-by Yan Zhai<[email protected]>
---
v2->v3: added missing report tags

Quoted 7 lines

---
  net/ipv4/syncookies.c | 2 +-
  net/ipv4/tcp_input.c  | 2 +-
  net/ipv4/tcp_ipv4.c   | 6 +++---
  net/ipv6/syncookies.c | 2 +-
  net/ipv6/tcp_ipv6.c   | 6 +++---
  5 files changed, 9 insertions(+), 9 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #11 lore raw

PATCH v5 6/7 udp: use sk_skb_reason_drop to free rx packets

In reply to Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.

Reported-by kernel test robot <[email protected]>

Closes https://lore.kernel.org/r/[email protected]/ open here

Signed-off-by Yan Zhai <[email protected]>

---
v2->v3: added missing report tags

---
 net/ipv4/udp.c | 10 +++++-----
 net/ipv6/udp.c | 10 +++++-----
 2 files changed, 10 insertions(+), 10 deletions(-)

net/ipv4/udp.c +5 -5

index 189c9113fe9a..ecafb1695999 100644
@@ -2074,7 +2074,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 		trace_udp_fail_queue_rcv_skb(rc, sk, skb);
-		kfree_skb_reason(skb, drop_reason);
+		sk_skb_reason_drop(sk, skb, drop_reason);
 		return -1;
 	}

@@ -2196,7 +2196,7 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 drop:
 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 	atomic_inc(&sk->sk_drops);
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return -1;
 }

@@ -2383,7 +2383,7 @@ static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 		   int proto)
 {
-	struct sock *sk;
+	struct sock *sk = NULL;
 	struct udphdr *uh;
 	unsigned short ulen;
 	struct rtable *rt = skb_rtable(skb);

@@ -2460,7 +2460,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	 * Hmm.  We got an UDP packet to a port to which we
 	 * don't wanna listen.  Ignore it.
 	 */
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 
 short_packet:

@@ -2485,7 +2485,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
 drop:
 	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 }

net/ipv6/udp.c +5 -5

index c81a07ac0463..b56f0b9f4307 100644
@@ -673,7 +673,7 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 		trace_udp_fail_queue_rcv_skb(rc, sk, skb);
-		kfree_skb_reason(skb, drop_reason);
+		sk_skb_reason_drop(sk, skb, drop_reason);
 		return -1;
 	}

@@ -776,7 +776,7 @@ static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 drop:
 	__UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 	atomic_inc(&sk->sk_drops);
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return -1;
 }

@@ -940,8 +940,8 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	const struct in6_addr *saddr, *daddr;
 	struct net *net = dev_net(skb->dev);
+	struct sock *sk = NULL;
 	struct udphdr *uh;
-	struct sock *sk;
 	bool refcounted;
 	u32 ulen = 0;

@@ -1033,7 +1033,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	__UDP6_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	return 0;
 
 short_packet:

@@ -1054,7 +1054,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
 discard:
 	__UDP6_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
-	kfree_skb_reason(skb, reason);
+	sk_skb_reason_drop(sk, skb, reason);
 	return 0;
 }

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 6/7

2024-06-18 06:22 UTC #12 lore raw

Re: [PATCH net-next v5 6/7] udp: use sk_skb_reason_drop to free rx packets

Quoted 6 lines · Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.
Reported-by kernel test robot<[email protected]>
Closes https://lore.kernel.org/r/[email protected]/ open here
Signed-off-by Yan Zhai<[email protected]>

Quoted 6 lines

---
v2->v3: added missing report tags

---
  net/ipv4/udp.c | 10 +++++-----
  net/ipv6/udp.c | 10 +++++-----
  2 files changed, 10 insertions(+), 10 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Yan Zhai

author

2024-06-17 18:09 UTC #13 lore raw

PATCH v5 7/7 af_packet: use sk_skb_reason_drop to free rx packets

In reply to Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.

Reported-by kernel test robot <[email protected]>

Closes https://lore.kernel.org/r/[email protected]/ open here

Signed-off-by Yan Zhai <[email protected]>

---
v2->v3: fixed uninitialized sk, added missing report tags.

---
 net/packet/af_packet.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

net/packet/af_packet.c +5 -5

index fce390887591..42d29b8a84fc 100644
@@ -2121,7 +2121,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
 		      struct packet_type *pt, struct net_device *orig_dev)
 {
 	enum skb_drop_reason drop_reason = SKB_CONSUMED;
-	struct sock *sk;
+	struct sock *sk = NULL;
 	struct sockaddr_ll *sll;
 	struct packet_sock *po;
 	u8 *skb_head = skb->data;

@@ -2226,7 +2226,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
 		skb->len = skb_len;
 	}
 drop:
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 }

@@ -2234,7 +2234,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		       struct packet_type *pt, struct net_device *orig_dev)
 {
 	enum skb_drop_reason drop_reason = SKB_CONSUMED;
-	struct sock *sk;
+	struct sock *sk = NULL;
 	struct packet_sock *po;
 	struct sockaddr_ll *sll;
 	union tpacket_uhdr h;

@@ -2494,7 +2494,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		skb->len = skb_len;
 	}
 drop:
-	kfree_skb_reason(skb, drop_reason);
+	sk_skb_reason_drop(sk, skb, drop_reason);
 	return 0;
 
 drop_n_account:

@@ -2503,7 +2503,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 	drop_reason = SKB_DROP_REASON_PACKET_SOCK_ERROR;
 
 	sk->sk_data_ready(sk);
-	kfree_skb_reason(copy_skb, drop_reason);
+	sk_skb_reason_drop(sk, copy_skb, drop_reason);
 	goto drop_n_restore;
 }

Signature · 1 line

2.30.2

Jesper Dangaard Brouer

Acked-by on v5 7/7

2024-06-18 06:24 UTC #14 lore raw

Re: [PATCH net-next v5 7/7] af_packet: use sk_skb_reason_drop to free rx packets

Quoted 11 lines · Yan Zhai

Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving socket to the tracepoint.
Reported-by kernel test robot<[email protected]>
Closes https://lore.kernel.org/r/[email protected]/ open here
Signed-off-by Yan Zhai<[email protected]>
---
v2->v3: fixed uninitialized sk, added missing report tags.
---
  net/packet/af_packet.c | 10 +++++-----
  1 file changed, 5 insertions(+), 5 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

[email protected]

CI Applied

2024-06-19 11:50 UTC #15 lore raw

In reply to Yan Zhai

This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Hello:

This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Quoted 10 lines · On Mon, 17 Jun 2024 11:09:00 -0700 you wrote:

We set up our production packet drop monitoring around the kfree_skb tracepoint. While this tracepoint is extremely valuable for diagnosing critical problems, it also has some limitation with drops on the local receive path: this tracepoint can only inspect the dropped skb itself, but such skb might not carry enough information to:
1. determine in which netns/container this skb gets dropped
2. determine by which socket/service this skb oughts to be received
[...]

Here is the summary with links:
- [net-next,v5,1/7] net: add rx_sk to trace_kfree_skb

    https://git.kernel.org/netdev/net-next/c/c53795d48ee8
  - [net-next,v5,2/7] net: introduce sk_skb_reason_drop function
    https://git.kernel.org/netdev/net-next/c/ba8de796baf4
  - [net-next,v5,3/7] ping: use sk_skb_reason_drop to free rx packets
    https://git.kernel.org/netdev/net-next/c/7467de17635f
  - [net-next,v5,4/7] net: raw: use sk_skb_reason_drop to free rx packets
    https://git.kernel.org/netdev/net-next/c/ce9a2424e9da
  - [net-next,v5,5/7] tcp: use sk_skb_reason_drop to free rx packets
    https://git.kernel.org/netdev/net-next/c/46a02aa35752
  - [net-next,v5,6/7] udp: use sk_skb_reason_drop to free rx packets
    https://git.kernel.org/netdev/net-next/c/fc0cc9248843
  - [net-next,v5,7/7] af_packet: use sk_skb_reason_drop to free rx packets
    https://git.kernel.org/netdev/net-next/c/e2e7d78d9a25

You are awesome, thank you!

Signature · 2 lines

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