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* [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb
@ 2022-03-04 14:55 Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 1/3] net: tap: track dropped skb via kfree_skb_reason() Dongli Zhang
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Dongli Zhang @ 2022-03-04 14:55 UTC (permalink / raw)
  To: netdev, bpf
  Cc: linux-kernel, davem, kuba, rostedt, mingo, ast, daniel, andrii,
	imagedong, joao.m.martins, joe.jin, dsahern, edumazet

The commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") has
introduced the kfree_skb_reason() to help track the reason.

The tun and tap are commonly used as virtio-net/vhost-net backend. This is to
use kfree_skb_reason() to trace the dropped skb for those two drivers. 

Changed since v1:
- I have renamed many of the reasons since v1. I make them as generic as
  possible so that they can be re-used by core networking and drivers.

Changed since v2:
- declare drop_reason as type "enum skb_drop_reason"
- handle the drop in skb_list_walk_safe() case for tap driver, and
  kfree_skb_list_reason() is introduced

Changed since v3 (only for PATCH 4/4):
- rename to TAP_FILTER and TAP_TXFILTER
- honor reverse xmas tree style declaration for 'drop_reason' in
  tun_net_xmit()

Changed since v4:
- make kfree_skb_list() static inline
- add 'computation' to SKB_CSUM comment
- change COPY_DATA to UCOPY_FAULT
- add 'metadata' to DEV_HDR comment
- expand comment on DEV_READY
- change SKB_TRIM to NOMEM
- chnage SKB_PULL to HDR_TRUNC
Changed since v5:
- rebase to net-next


The following reasons are introduced.

- SKB_DROP_REASON_SKB_CSUM
- SKB_DROP_REASON_SKB_GSO_SEG
- SKB_DROP_REASON_SKB_UCOPY_FAULT
- SKB_DROP_REASON_DEV_HDR
- SKB_DROP_REASON_FULL_RING
- SKB_DROP_REASON_DEV_READY
- SKB_DROP_REASON_NOMEM
- SKB_DROP_REASON_HDR_TRUNC
- SKB_DROP_REASON_TAP_FILTER
- SKB_DROP_REASON_TAP_TXFILTER


This is the output for TUN device.

# cat /sys/kernel/debug/tracing/trace_pipe
          <idle>-0       [029] ..s1.   450.727651: kfree_skb: skbaddr=0000000023d235cc protocol=0 location=00000000a6748854 reason: NOT_SPECIFIED
          <idle>-0       [000] b.s3.   451.165671: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   453.149650: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   455.133576: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   457.117566: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING


This is the output for TAP device.

# cat /sys/kernel/debug/tracing/trace_pipe
          arping-7053    [006] ..s1.  1000.047753: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          <idle>-0       [022] ..s1.  1000.778514: kfree_skb: skbaddr=000000002c1e706c protocol=0 location=00000000a6748854 reason: NOT_SPECIFIED
          arping-7053    [006] ..s1.  1001.047830: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          arping-7053    [006] ..s1.  1002.047918: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          arping-7053    [006] ..s1.  1003.048017: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING


 drivers/net/tap.c          | 35 +++++++++++++++++++++++++----------
 drivers/net/tun.c          | 38 ++++++++++++++++++++++++++++++--------
 include/linux/skbuff.h     | 31 +++++++++++++++++++++++++++++++
 include/trace/events/skb.h | 10 ++++++++++
 4 files changed, 96 insertions(+), 18 deletions(-)


Thank you very much!

Dongli Zhang



^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH net-next v6 1/3] net: tap: track dropped skb via kfree_skb_reason()
  2022-03-04 14:55 [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
@ 2022-03-04 14:55 ` Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 2/3] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement" Dongli Zhang
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Dongli Zhang @ 2022-03-04 14:55 UTC (permalink / raw)
  To: netdev, bpf
  Cc: linux-kernel, davem, kuba, rostedt, mingo, ast, daniel, andrii,
	imagedong, joao.m.martins, joe.jin, dsahern, edumazet

The TAP can be used as vhost-net backend. E.g., the tap_handle_frame() is
the interface to forward the skb from TAP to vhost-net/virtio-net.

However, there are many "goto drop" in the TAP driver. Therefore, the
kfree_skb_reason() is involved at each "goto drop" to help userspace
ftrace/ebpf to track the reason for the loss of packets.

The below reasons are introduced:

- SKB_DROP_REASON_SKB_CSUM
- SKB_DROP_REASON_SKB_GSO_SEG
- SKB_DROP_REASON_SKB_UCOPY_FAULT
- SKB_DROP_REASON_DEV_HDR
- SKB_DROP_REASON_FULL_RING

Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
Changed since v1:
  - revise the reason name
Changed since v2:
  - declare drop_reason as type "enum skb_drop_reason"
  - handle the drop in skb_list_walk_safe() case
Changed since v4:
  - add 'computation' to SKB_CSUM comment
  - change COPY_DATA to UCOPY_FAULT
  - add 'metadata' to DEV_HDR comment
Changed since v5:
  - rebase to net-next

 drivers/net/tap.c          | 35 +++++++++++++++++++++++++----------
 include/linux/skbuff.h     | 13 +++++++++++++
 include/trace/events/skb.h |  5 +++++
 3 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index ba2ef5437e16..c3d42062559d 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -322,6 +322,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 	struct tap_dev *tap;
 	struct tap_queue *q;
 	netdev_features_t features = TAP_FEATURES;
+	enum skb_drop_reason drop_reason;
 
 	tap = tap_dev_get_rcu(dev);
 	if (!tap)
@@ -343,12 +344,16 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 		struct sk_buff *segs = __skb_gso_segment(skb, features, false);
 		struct sk_buff *next;
 
-		if (IS_ERR(segs))
+		if (IS_ERR(segs)) {
+			drop_reason = SKB_DROP_REASON_SKB_GSO_SEG;
 			goto drop;
+		}
 
 		if (!segs) {
-			if (ptr_ring_produce(&q->ring, skb))
+			if (ptr_ring_produce(&q->ring, skb)) {
+				drop_reason = SKB_DROP_REASON_FULL_RING;
 				goto drop;
+			}
 			goto wake_up;
 		}
 
@@ -356,8 +361,9 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 		skb_list_walk_safe(segs, skb, next) {
 			skb_mark_not_on_list(skb);
 			if (ptr_ring_produce(&q->ring, skb)) {
-				kfree_skb(skb);
-				kfree_skb_list(next);
+				drop_reason = SKB_DROP_REASON_FULL_RING;
+				kfree_skb_reason(skb, drop_reason);
+				kfree_skb_list_reason(next, drop_reason);
 				break;
 			}
 		}
@@ -369,10 +375,14 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 		 */
 		if (skb->ip_summed == CHECKSUM_PARTIAL &&
 		    !(features & NETIF_F_CSUM_MASK) &&
-		    skb_checksum_help(skb))
+		    skb_checksum_help(skb)) {
+			drop_reason = SKB_DROP_REASON_SKB_CSUM;
 			goto drop;
-		if (ptr_ring_produce(&q->ring, skb))
+		}
+		if (ptr_ring_produce(&q->ring, skb)) {
+			drop_reason = SKB_DROP_REASON_FULL_RING;
 			goto drop;
+		}
 	}
 
 wake_up:
@@ -383,7 +393,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
 	/* Count errors/drops only here, thus don't care about args. */
 	if (tap->count_rx_dropped)
 		tap->count_rx_dropped(tap);
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 	return RX_HANDLER_CONSUMED;
 }
 EXPORT_SYMBOL_GPL(tap_handle_frame);
@@ -632,6 +642,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 	int depth;
 	bool zerocopy = false;
 	size_t linear;
+	enum skb_drop_reason drop_reason;
 
 	if (q->flags & IFF_VNET_HDR) {
 		vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
@@ -696,8 +707,10 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 	else
 		err = skb_copy_datagram_from_iter(skb, 0, from, len);
 
-	if (err)
+	if (err) {
+		drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
 		goto err_kfree;
+	}
 
 	skb_set_network_header(skb, ETH_HLEN);
 	skb_reset_mac_header(skb);
@@ -706,8 +719,10 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 	if (vnet_hdr_len) {
 		err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
 					    tap_is_little_endian(q));
-		if (err)
+		if (err) {
+			drop_reason = SKB_DROP_REASON_DEV_HDR;
 			goto err_kfree;
+		}
 	}
 
 	skb_probe_transport_header(skb);
@@ -738,7 +753,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 	return total_len;
 
 err_kfree:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 
 err:
 	rcu_read_lock();
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2be263184d1e..67cfff4065b6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -412,6 +412,19 @@ enum skb_drop_reason {
 					 * this means that L3 protocol is
 					 * not supported
 					 */
+	SKB_DROP_REASON_SKB_CSUM,	/* sk_buff checksum computation
+					 * error
+					 */
+	SKB_DROP_REASON_SKB_GSO_SEG,	/* gso segmentation error */
+	SKB_DROP_REASON_SKB_UCOPY_FAULT,	/* failed to copy data from
+						 * user space, e.g., via
+						 * zerocopy_sg_from_iter()
+						 * or skb_orphan_frags_rx()
+						 */
+	SKB_DROP_REASON_DEV_HDR,	/* device driver specific
+					 * header/metadata is invalid
+					 */
+	SKB_DROP_REASON_FULL_RING,	/* ring buffer is full */
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index c0769d943f8e..240e7e7591fc 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -51,6 +51,11 @@
 	EM(SKB_DROP_REASON_XDP, XDP)				\
 	EM(SKB_DROP_REASON_TC_INGRESS, TC_INGRESS)		\
 	EM(SKB_DROP_REASON_PTYPE_ABSENT, PTYPE_ABSENT)		\
+	EM(SKB_DROP_REASON_SKB_CSUM, SKB_CSUM)			\
+	EM(SKB_DROP_REASON_SKB_GSO_SEG, SKB_GSO_SEG)		\
+	EM(SKB_DROP_REASON_SKB_UCOPY_FAULT, SKB_UCOPY_FAULT)	\
+	EM(SKB_DROP_REASON_DEV_HDR, DEV_HDR)			\
+	EM(SKB_DROP_REASON_FULL_RING, FULL_RING)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [PATCH net-next v6 2/3] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement"
  2022-03-04 14:55 [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 1/3] net: tap: track dropped skb via kfree_skb_reason() Dongli Zhang
@ 2022-03-04 14:55 ` Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 3/3] net: tun: track dropped skb via kfree_skb_reason() Dongli Zhang
  2022-03-06 11:40 ` [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: Dongli Zhang @ 2022-03-04 14:55 UTC (permalink / raw)
  To: netdev, bpf
  Cc: linux-kernel, davem, kuba, rostedt, mingo, ast, daniel, andrii,
	imagedong, joao.m.martins, joe.jin, dsahern, edumazet

No functional change.

Just to split the if statement into different conditions to use
kfree_skb_reason() to trace the reason later.

Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
 drivers/net/tun.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 2a0d8a5d7aec..6e06c846fe82 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1086,7 +1086,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto drop;
 
 	len = run_ebpf_filter(tun, skb, len);
-	if (len == 0 || pskb_trim(skb, len))
+	if (len == 0)
+		goto drop;
+
+	if (pskb_trim(skb, len))
 		goto drop;
 
 	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [PATCH net-next v6 3/3] net: tun: track dropped skb via kfree_skb_reason()
  2022-03-04 14:55 [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 1/3] net: tap: track dropped skb via kfree_skb_reason() Dongli Zhang
  2022-03-04 14:55 ` [PATCH net-next v6 2/3] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement" Dongli Zhang
@ 2022-03-04 14:55 ` Dongli Zhang
  2022-03-06 11:40 ` [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: Dongli Zhang @ 2022-03-04 14:55 UTC (permalink / raw)
  To: netdev, bpf
  Cc: linux-kernel, davem, kuba, rostedt, mingo, ast, daniel, andrii,
	imagedong, joao.m.martins, joe.jin, dsahern, edumazet

The TUN can be used as vhost-net backend. E.g, the tun_net_xmit() is the
interface to forward the skb from TUN to vhost-net/virtio-net.

However, there are many "goto drop" in the TUN driver. Therefore, the
kfree_skb_reason() is involved at each "goto drop" to help userspace
ftrace/ebpf to track the reason for the loss of packets.

The below reasons are introduced:

- SKB_DROP_REASON_DEV_READY
- SKB_DROP_REASON_NOMEM
- SKB_DROP_REASON_HDR_TRUNC
- SKB_DROP_REASON_TAP_FILTER
- SKB_DROP_REASON_TAP_TXFILTER

Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
Changed since v1:
  - revise the reason name
Changed since v2:
  - declare drop_reason as type "enum skb_drop_reason"
Changed since v3:
  - rename to TAP_FILTER and TAP_TXFILTER
  - honor reverse xmas tree style declaration for 'drop_reason' in
    tun_net_xmit()
Changed since v4:
  - expand comment on DEV_READY
  - change SKB_TRIM to NOMEM
  - chnage SKB_PULL to HDR_TRUNC

 drivers/net/tun.c          | 37 ++++++++++++++++++++++++++++---------
 include/linux/skbuff.h     | 18 ++++++++++++++++++
 include/trace/events/skb.h |  5 +++++
 3 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 6e06c846fe82..bab92e489fba 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1058,6 +1058,7 @@ static unsigned int run_ebpf_filter(struct tun_struct *tun,
 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct tun_struct *tun = netdev_priv(dev);
+	enum skb_drop_reason drop_reason;
 	int txq = skb->queue_mapping;
 	struct netdev_queue *queue;
 	struct tun_file *tfile;
@@ -1067,8 +1068,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	tfile = rcu_dereference(tun->tfiles[txq]);
 
 	/* Drop packet if interface is not attached */
-	if (!tfile)
+	if (!tfile) {
+		drop_reason = SKB_DROP_REASON_DEV_READY;
 		goto drop;
+	}
 
 	if (!rcu_dereference(tun->steering_prog))
 		tun_automq_xmit(tun, skb);
@@ -1078,22 +1081,32 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Drop if the filter does not like it.
 	 * This is a noop if the filter is disabled.
 	 * Filter can be enabled only for the TAP devices. */
-	if (!check_filter(&tun->txflt, skb))
+	if (!check_filter(&tun->txflt, skb)) {
+		drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
 		goto drop;
+	}
 
 	if (tfile->socket.sk->sk_filter &&
-	    sk_filter(tfile->socket.sk, skb))
+	    sk_filter(tfile->socket.sk, skb)) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		goto drop;
+	}
 
 	len = run_ebpf_filter(tun, skb, len);
-	if (len == 0)
+	if (len == 0) {
+		drop_reason = SKB_DROP_REASON_TAP_FILTER;
 		goto drop;
+	}
 
-	if (pskb_trim(skb, len))
+	if (pskb_trim(skb, len)) {
+		drop_reason = SKB_DROP_REASON_NOMEM;
 		goto drop;
+	}
 
-	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
+	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
+		drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
 		goto drop;
+	}
 
 	skb_tx_timestamp(skb);
 
@@ -1104,8 +1117,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	nf_reset_ct(skb);
 
-	if (ptr_ring_produce(&tfile->tx_ring, skb))
+	if (ptr_ring_produce(&tfile->tx_ring, skb)) {
+		drop_reason = SKB_DROP_REASON_FULL_RING;
 		goto drop;
+	}
 
 	/* NETIF_F_LLTX requires to do our own update of trans_start */
 	queue = netdev_get_tx_queue(dev, txq);
@@ -1122,7 +1137,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 drop:
 	atomic_long_inc(&dev->tx_dropped);
 	skb_tx_error(skb);
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 	rcu_read_unlock();
 	return NET_XMIT_DROP;
 }
@@ -1720,6 +1735,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	u32 rxhash = 0;
 	int skb_xdp = 1;
 	bool frags = tun_napi_frags_enabled(tfile);
+	enum skb_drop_reason drop_reason;
 
 	if (!(tun->flags & IFF_NO_PI)) {
 		if (len < sizeof(pi))
@@ -1823,9 +1839,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 		if (err) {
 			err = -EFAULT;
+			drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
 drop:
 			atomic_long_inc(&tun->dev->rx_dropped);
-			kfree_skb(skb);
+			kfree_skb_reason(skb, drop_reason);
 			if (frags) {
 				tfile->napi.skb = NULL;
 				mutex_unlock(&tfile->napi_mutex);
@@ -1872,6 +1889,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	case IFF_TAP:
 		if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
 			err = -ENOMEM;
+			drop_reason = SKB_DROP_REASON_HDR_TRUNC;
 			goto drop;
 		}
 		skb->protocol = eth_type_trans(skb, tun->dev);
@@ -1925,6 +1943,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	if (unlikely(!(tun->dev->flags & IFF_UP))) {
 		err = -EIO;
 		rcu_read_unlock();
+		drop_reason = SKB_DROP_REASON_DEV_READY;
 		goto drop;
 	}
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 67cfff4065b6..34f572271c0c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -424,7 +424,25 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_DEV_HDR,	/* device driver specific
 					 * header/metadata is invalid
 					 */
+	/* the device is not ready to xmit/recv due to any of its data
+	 * structure that is not up/ready/initialized, e.g., the IFF_UP is
+	 * not set, or driver specific tun->tfiles[txq] is not initialized
+	 */
+	SKB_DROP_REASON_DEV_READY,
 	SKB_DROP_REASON_FULL_RING,	/* ring buffer is full */
+	SKB_DROP_REASON_NOMEM,		/* error due to OOM */
+	SKB_DROP_REASON_HDR_TRUNC,      /* failed to trunc/extract the header
+					 * from networking data, e.g., failed
+					 * to pull the protocol header from
+					 * frags via pskb_may_pull()
+					 */
+	SKB_DROP_REASON_TAP_FILTER,     /* dropped by (ebpf) filter directly
+					 * attached to tun/tap, e.g., via
+					 * TUNSETFILTEREBPF
+					 */
+	SKB_DROP_REASON_TAP_TXFILTER,	/* dropped by tx filter implemented
+					 * at tun/tap, e.g., check_filter()
+					 */
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 240e7e7591fc..e1670e1e4934 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -55,7 +55,12 @@
 	EM(SKB_DROP_REASON_SKB_GSO_SEG, SKB_GSO_SEG)		\
 	EM(SKB_DROP_REASON_SKB_UCOPY_FAULT, SKB_UCOPY_FAULT)	\
 	EM(SKB_DROP_REASON_DEV_HDR, DEV_HDR)			\
+	EM(SKB_DROP_REASON_DEV_READY, DEV_READY)		\
 	EM(SKB_DROP_REASON_FULL_RING, FULL_RING)		\
+	EM(SKB_DROP_REASON_NOMEM, NOMEM)			\
+	EM(SKB_DROP_REASON_HDR_TRUNC, HDR_TRUNC)		\
+	EM(SKB_DROP_REASON_TAP_FILTER, TAP_FILTER)		\
+	EM(SKB_DROP_REASON_TAP_TXFILTER, TAP_TXFILTER)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb
  2022-03-04 14:55 [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
                   ` (2 preceding siblings ...)
  2022-03-04 14:55 ` [PATCH net-next v6 3/3] net: tun: track dropped skb via kfree_skb_reason() Dongli Zhang
@ 2022-03-06 11:40 ` patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-03-06 11:40 UTC (permalink / raw)
  To: Dongli Zhang
  Cc: netdev, bpf, linux-kernel, davem, kuba, rostedt, mingo, ast,
	daniel, andrii, imagedong, joao.m.martins, joe.jin, dsahern,
	edumazet

Hello:

This series was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri,  4 Mar 2022 06:55:04 -0800 you wrote:
> The commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") has
> introduced the kfree_skb_reason() to help track the reason.
> 
> The tun and tap are commonly used as virtio-net/vhost-net backend. This is to
> use kfree_skb_reason() to trace the dropped skb for those two drivers.
> 
> Changed since v1:
> - I have renamed many of the reasons since v1. I make them as generic as
>   possible so that they can be re-used by core networking and drivers.
> 
> [...]

Here is the summary with links:
  - [net-next,v6,1/3] net: tap: track dropped skb via kfree_skb_reason()
    https://git.kernel.org/netdev/net-next/c/736f16de75f9
  - [net-next,v6,2/3] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement"
    https://git.kernel.org/netdev/net-next/c/45a15d89fbcd
  - [net-next,v6,3/3] net: tun: track dropped skb via kfree_skb_reason()
    https://git.kernel.org/netdev/net-next/c/4b4f052e2d89

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-03-06 11:40 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-04 14:55 [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
2022-03-04 14:55 ` [PATCH net-next v6 1/3] net: tap: track dropped skb via kfree_skb_reason() Dongli Zhang
2022-03-04 14:55 ` [PATCH net-next v6 2/3] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement" Dongli Zhang
2022-03-04 14:55 ` [PATCH net-next v6 3/3] net: tun: track dropped skb via kfree_skb_reason() Dongli Zhang
2022-03-06 11:40 ` [PATCH net-next v6 0/3] tun/tap: use kfree_skb_reason() to trace dropped skb patchwork-bot+netdevbpf

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