From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF01AC43217 for ; Sun, 9 Jan 2022 06:38:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235229AbiAIGh0 (ORCPT ); Sun, 9 Jan 2022 01:37:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235220AbiAIGhZ (ORCPT ); Sun, 9 Jan 2022 01:37:25 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35D57C061401; Sat, 8 Jan 2022 22:37:25 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id 59-20020a17090a09c100b001b34a13745eso11359656pjo.5; Sat, 08 Jan 2022 22:37:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+Way90yUz+/oARc0V+ElMdCYBNNb7orbnuEP+2suGKw=; b=gNqXY4fk14C8cThWFuzOgCWn2id4XYgRUgBYjlNWmxwjMt7SrXBKqWNp4xVf44l8Il FkEjsly7mSkilUzyexxtkHw7shNBYTmrffzJ7gxh+MpZeWOZhPnM8v7dWwVXZbABw1LV RUgh6lp3e0puwCEvIInVBTa8nNlX7a56TXe/tQeIix2CLTQCXUNZwV3LzDqzNkcr81tD VhfRz1r6dG8SEKRzIJWvKxa+w+HQ1B5vsU5iFSuRy626pVz8k/MMZG9up+CkCSJXHjx4 qsEHueT+pZxHvBZgFuKnPtrN1Ovyr9U3m9pjifGnRL6Kiqofog2YoTT/uSfTCgi3Dj6J ngoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+Way90yUz+/oARc0V+ElMdCYBNNb7orbnuEP+2suGKw=; b=XXspmUZUH2CZLw4gKVMeMyCTQxoF0xXJrU4BRlUsQ9ZPlghlNjC6pVxJXnGT+gejS7 ecHVBEGV1QZbhEGRvRMbL2s0N0pH0h25aWdw2R47vbHWlsDMdxzgRpkAQfsSvCusOu56 RTRnkcok7Sl31yEV72cYZXI6qS9cALkKJ6DpaPqyo84X2InX5/DlNULZloX7vZovAyWh NHWR7/WtbX4ibpO8oEdaSQO8uflbufPpzvfpzVWJZDcun8h/wIkNYe2r0vlm1c0GlDR+ L7aOCAmkDTfK95TbBPEGxP4Aq+yXE6ZjOWM9unWBQBPEvQ0gbnaQ4UWJ8fb9vZ9Sss1V 6E3A== X-Gm-Message-State: AOAM532R0dznIMSSs8vX/b2ZaJhEH5FavhOo0aqiPSJVIXpb+FUw+SrG J2GAKhuiTChg/VpIcxfCWTKbmk2cT2U= X-Google-Smtp-Source: ABdhPJw80g9m/42eGalDFyQ+9uLUwf4qBPbQwsfRb/h150WFC9fJ3B23cGoq1DmNPZUottDaf3fDSA== X-Received: by 2002:a17:90b:688:: with SMTP id m8mr18207838pjz.62.1641710244689; Sat, 08 Jan 2022 22:37:24 -0800 (PST) Received: from localhost.localdomain ([43.132.141.4]) by smtp.gmail.com with ESMTPSA id my5sm5892042pjb.5.2022.01.08.22.37.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 08 Jan 2022 22:37:24 -0800 (PST) From: menglong8.dong@gmail.com X-Google-Original-From: imagedong@tencent.com To: rostedt@goodmis.org, dsahern@kernel.org Cc: mingo@redhat.com, davem@davemloft.net, kuba@kernel.org, nhorman@tuxdriver.com, edumazet@google.com, yoshfuji@linux-ipv6.org, alobakin@pm.me, willemb@google.com, cong.wang@bytedance.com, keescook@chromium.org, pabeni@redhat.com, talalahmad@google.com, haokexin@gmail.com, ilias.apalodimas@linaro.org, memxor@gmail.com, atenart@kernel.org, bigeasy@linutronix.de, weiwan@google.com, arnd@arndb.de, vvs@virtuozzo.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, jonathan.lemon@gmail.com, imagedong@tencent.com Subject: [PATCH v4 net-next 1/3] net: skb: introduce kfree_skb_reason() Date: Sun, 9 Jan 2022 14:36:26 +0800 Message-Id: <20220109063628.526990-2-imagedong@tencent.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220109063628.526990-1-imagedong@tencent.com> References: <20220109063628.526990-1-imagedong@tencent.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Menglong Dong Introduce the interface kfree_skb_reason(), which is able 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. All drop reasons are defined in the enum 'skb_drop_reason', and they will be print as string in 'kfree_skb' tracepoint in format of 'reason: XXX'. ( Maybe the reasons should be defined in a uapi header file, so that user space can use them? ) Signed-off-by: Menglong Dong --- v4: - fix some code style in skb.h v3: - rename kfree_skb_with_reason() to kfree_skb_reason() - turn kfree_skb() into a static inline calling kfree_skb_reason() --- include/linux/skbuff.h | 23 ++++++++++++++++++++++- include/trace/events/skb.h | 36 +++++++++++++++++++++++++++++------- net/core/dev.c | 3 ++- net/core/drop_monitor.c | 10 +++++++--- net/core/skbuff.c | 12 +++++++----- 5 files changed, 67 insertions(+), 17 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 642acb0d1646..ef0870abc791 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_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. @@ -1085,8 +1096,18 @@ static inline bool skb_unref(struct sk_buff *skb) return true; } +void kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason); + +/** + * kfree_skb - free an sk_buff with 'NOT_SPECIFIED' reason + * @skb: buffer to free + */ +static inline void kfree_skb(struct sk_buff *skb) +{ + kfree_skb_reason(skb, SKB_DROP_REASON_NOT_SPECIFIED); +} + void skb_release_head_state(struct sk_buff *skb); -void kfree_skb(struct sk_buff *skb); 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..294c61bbe44b 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -9,29 +9,51 @@ #include #include +#define TRACE_SKB_DROP_REASON \ + EM(SKB_DROP_REASON_NOT_SPECIFIED, NOT_SPECIFIED) \ + EMe(SKB_DROP_REASON_MAX, 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 83a4089990a0..84a0d9542fe9 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 e514a36bcffc..0118f0afaa4f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -759,21 +759,23 @@ void __kfree_skb(struct sk_buff *skb) EXPORT_SYMBOL(__kfree_skb); /** - * kfree_skb - free an sk_buff + * kfree_skb_reason - free an sk_buff with special reason * @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. + * hit zero. Meanwhile, pass the drop reason to 'kfree_skb' + * tracepoint. */ -void kfree_skb(struct sk_buff *skb) +void kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) { if (!skb_unref(skb)) return; - trace_kfree_skb(skb, __builtin_return_address(0)); + trace_kfree_skb(skb, __builtin_return_address(0), reason); __kfree_skb(skb); } -EXPORT_SYMBOL(kfree_skb); +EXPORT_SYMBOL(kfree_skb_reason); void kfree_skb_list(struct sk_buff *segs) { -- 2.34.1