Messages in this thread Patch in this message | | | From | menglong8.dong@gmail ... | Subject | [PATCH v2 net-next 1/3] net: skb: introduce kfree_skb_with_reason() | Date | Thu, 30 Dec 2021 17:32:38 +0800 |
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From: Menglong Dong <imagedong@tencent.com>
Introduce the interface kfree_skb_with_reason(), which is used to pass the reason why the skb is dropped to 'kfree_skb' tracepoint.
Add the 'reason' field to 'trace_kfree_skb', therefor user can get more detail information about abnormal skb with 'drop_monitor' or eBPF.
Signed-off-by: Menglong Dong <imagedong@tencent.com> --- include/linux/skbuff.h | 13 +++++++++++++ include/trace/events/skb.h | 36 +++++++++++++++++++++++++++++------- net/core/dev.c | 3 ++- net/core/drop_monitor.c | 10 +++++++--- net/core/skbuff.c | 22 +++++++++++++++++++++- 5 files changed, 72 insertions(+), 12 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index aa9d42724e20..3620b3ff2154 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -305,6 +305,17 @@ struct sk_buff_head { struct sk_buff; +/* The reason of skb drop, which is used in kfree_skb_with_reason(). + * en...maybe they should be splited by group? + * + * Each item here should also be in 'TRACE_SKB_DROP_REASON', which is + * used to translate the reason to string. + */ +enum skb_drop_reason { + SKB_DROP_REASON_NOT_SPECIFIED, + SKB_DROP_REASON_MAX, +}; + /* To allow 64K frame to be packed as single skb without frag_list we * require 64K/PAGE_SIZE pages plus 1 additional page to allow for * buffers which do not start on a page boundary. @@ -1087,6 +1098,8 @@ static inline bool skb_unref(struct sk_buff *skb) void skb_release_head_state(struct sk_buff *skb); void kfree_skb(struct sk_buff *skb); +void kfree_skb_with_reason(struct sk_buff *skb, + enum skb_drop_reason reason); void kfree_skb_list(struct sk_buff *segs); void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt); void skb_tx_error(struct sk_buff *skb); diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h index 9e92f22eb086..cab1c08a30cd 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -9,29 +9,51 @@ #include <linux/netdevice.h> #include <linux/tracepoint.h> +#define TRACE_SKB_DROP_REASON \ + EM(SKB_DROP_REASON_NOT_SPECIFIED, NOT_SPECIFIED) \ + EMe(SKB_DROP_REASON_MAX, HAHA_MAX) + +#undef EM +#undef EMe + +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define EMe(a, b) TRACE_DEFINE_ENUM(a); + +TRACE_SKB_DROP_REASON + +#undef EM +#undef EMe +#define EM(a, b) { a, #b }, +#define EMe(a, b) { a, #b } + + /* * Tracepoint for free an sk_buff: */ TRACE_EVENT(kfree_skb, - TP_PROTO(struct sk_buff *skb, void *location), + TP_PROTO(struct sk_buff *skb, void *location, + enum skb_drop_reason reason), - TP_ARGS(skb, location), + TP_ARGS(skb, location, reason), TP_STRUCT__entry( - __field( void *, skbaddr ) - __field( void *, location ) - __field( unsigned short, protocol ) + __field(void *, skbaddr) + __field(void *, location) + __field(unsigned short, protocol) + __field(enum skb_drop_reason, reason) ), TP_fast_assign( __entry->skbaddr = skb; __entry->location = location; __entry->protocol = ntohs(skb->protocol); + __entry->reason = reason; ), - TP_printk("skbaddr=%p protocol=%u location=%p", - __entry->skbaddr, __entry->protocol, __entry->location) + TP_printk("skbaddr=%p protocol=%u location=%p reason: %s", + __entry->skbaddr, __entry->protocol, __entry->location, + __print_symbolic(__entry->reason, TRACE_SKB_DROP_REASON)) ); TRACE_EVENT(consume_skb, diff --git a/net/core/dev.c b/net/core/dev.c index 644b9c8be3a8..9464dbf9e3d6 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4899,7 +4899,8 @@ static __latent_entropy void net_tx_action(struct softirq_action *h) if (likely(get_kfree_skb_cb(skb)->reason == SKB_REASON_CONSUMED)) trace_consume_skb(skb); else - trace_kfree_skb(skb, net_tx_action); + trace_kfree_skb(skb, net_tx_action, + SKB_DROP_REASON_NOT_SPECIFIED); if (skb->fclone != SKB_FCLONE_UNAVAILABLE) __kfree_skb(skb); diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 3d0ab2eec916..7b288a121a41 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -110,7 +110,8 @@ static u32 net_dm_queue_len = 1000; struct net_dm_alert_ops { void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, - void *location); + void *location, + enum skb_drop_reason reason); void (*napi_poll_probe)(void *ignore, struct napi_struct *napi, int work, int budget); void (*work_item_func)(struct work_struct *work); @@ -262,7 +263,9 @@ static void trace_drop_common(struct sk_buff *skb, void *location) spin_unlock_irqrestore(&data->lock, flags); } -static void trace_kfree_skb_hit(void *ignore, 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) { trace_drop_common(skb, location); } @@ -490,7 +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) + void *location, + enum skb_drop_reason reason) { ktime_t tstamp = ktime_get_real(); struct per_cpu_dm_data *data; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 275f7b8416fe..570dc022a8a1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -770,11 +770,31 @@ void kfree_skb(struct sk_buff *skb) if (!skb_unref(skb)) return; - trace_kfree_skb(skb, __builtin_return_address(0)); + trace_kfree_skb(skb, __builtin_return_address(0), + SKB_DROP_REASON_NOT_SPECIFIED); __kfree_skb(skb); } EXPORT_SYMBOL(kfree_skb); +/** + * kfree_skb_with_reason - free an sk_buff with reason + * @skb: buffer to free + * @reason: reason why this skb is dropped + * + * The same as kfree_skb() except that this function will pass + * the drop reason to 'kfree_skb' tracepoint. + */ +void kfree_skb_with_reason(struct sk_buff *skb, + enum skb_drop_reason reason) +{ + if (!skb_unref(skb)) + return; + + trace_kfree_skb(skb, __builtin_return_address(0), reason); + __kfree_skb(skb); +} +EXPORT_SYMBOL(kfree_skb_with_reason); + void kfree_skb_list(struct sk_buff *segs) { while (segs) { -- 2.30.2
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