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 X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47462C43463 for ; Fri, 18 Sep 2020 02:49:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13AB8235F8 for ; Fri, 18 Sep 2020 02:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600397371; bh=1S77m4row9Ck+TBXx2z25Pwb64xZDCNkJSlX5PfCtF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fXp1Qhqbc4z50YpYcuhmI4G5xV20oqCKWGXgdowD37VIgTCRLLJUNbI6pzpgh/Van WZvV/XxNIkwwxA0qxaGbjIx3WetEvoURja4yo+7IOjdf8nNqRr+HF82TtqyjOzA0db dROi6Yck5TMTi6tHo8R6uibTfjbQRAqygDY5su3o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728222AbgIRCJD (ORCPT ); Thu, 17 Sep 2020 22:09:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:60660 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726759AbgIRCJA (ORCPT ); Thu, 17 Sep 2020 22:09:00 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 58E562389E; Fri, 18 Sep 2020 02:08:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394939; bh=1S77m4row9Ck+TBXx2z25Pwb64xZDCNkJSlX5PfCtF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b54frm6rigxi28dU+rKEl+uD59iPOg/gn8qVMEsNymRG/dy8EefTne35Gr8C3dw4U MjYrvjY/TL+ldGdFeRSu0JTNcn6d6hYPT9+Isxtb8nBKI0UVc80F0HvhtOCNOYfRez QM7r9mzpLS9/THgnjNoSKKHRYMoxWBvAE1E1D+Nk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kevin Kou , Marcelo Ricardo Leitner , "David S . Miller" , Sasha Levin , linux-sctp@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 048/206] sctp: move trace_sctp_probe_path into sctp_outq_sack Date: Thu, 17 Sep 2020 22:05:24 -0400 Message-Id: <20200918020802.2065198-48-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020802.2065198-1-sashal@kernel.org> References: <20200918020802.2065198-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Kevin Kou [ Upstream commit f643ee295c1c63bc117fb052d4da681354d6f732 ] The original patch bringed in the "SCTP ACK tracking trace event" feature was committed at Dec.20, 2017, it replaced jprobe usage with trace events, and bringed in two trace events, one is TRACE_EVENT(sctp_probe), another one is TRACE_EVENT(sctp_probe_path). The original patch intended to trigger the trace_sctp_probe_path in TRACE_EVENT(sctp_probe) as below code, +TRACE_EVENT(sctp_probe, + + TP_PROTO(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk), + + TP_ARGS(ep, asoc, chunk), + + TP_STRUCT__entry( + __field(__u64, asoc) + __field(__u32, mark) + __field(__u16, bind_port) + __field(__u16, peer_port) + __field(__u32, pathmtu) + __field(__u32, rwnd) + __field(__u16, unack_data) + ), + + TP_fast_assign( + struct sk_buff *skb = chunk->skb; + + __entry->asoc = (unsigned long)asoc; + __entry->mark = skb->mark; + __entry->bind_port = ep->base.bind_addr.port; + __entry->peer_port = asoc->peer.port; + __entry->pathmtu = asoc->pathmtu; + __entry->rwnd = asoc->peer.rwnd; + __entry->unack_data = asoc->unack_data; + + if (trace_sctp_probe_path_enabled()) { + struct sctp_transport *sp; + + list_for_each_entry(sp, &asoc->peer.transport_addr_list, + transports) { + trace_sctp_probe_path(sp, asoc); + } + } + ), But I found it did not work when I did testing, and trace_sctp_probe_path had no output, I finally found that there is trace buffer lock operation(trace_event_buffer_reserve) in include/trace/trace_events.h: static notrace void \ trace_event_raw_event_##call(void *__data, proto) \ { \ struct trace_event_file *trace_file = __data; \ struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\ struct trace_event_buffer fbuffer; \ struct trace_event_raw_##call *entry; \ int __data_size; \ \ if (trace_trigger_soft_disabled(trace_file)) \ return; \ \ __data_size = trace_event_get_offsets_##call(&__data_offsets, args); \ \ entry = trace_event_buffer_reserve(&fbuffer, trace_file, \ sizeof(*entry) + __data_size); \ \ if (!entry) \ return; \ \ tstruct \ \ { assign; } \ \ trace_event_buffer_commit(&fbuffer); \ } The reason caused no output of trace_sctp_probe_path is that trace_sctp_probe_path written in TP_fast_assign part of TRACE_EVENT(sctp_probe), and it will be placed( { assign; } ) after the trace_event_buffer_reserve() when compiler expands Macro, entry = trace_event_buffer_reserve(&fbuffer, trace_file, \ sizeof(*entry) + __data_size); \ \ if (!entry) \ return; \ \ tstruct \ \ { assign; } \ so trace_sctp_probe_path finally can not acquire trace_event_buffer and return no output, that is to say the nest of tracepoint entry function is not allowed. The function call flow is: trace_sctp_probe() -> trace_event_raw_event_sctp_probe() -> lock buffer -> trace_sctp_probe_path() -> trace_event_raw_event_sctp_probe_path() --nested -> buffer has been locked and return no output. This patch is to remove trace_sctp_probe_path from the TP_fast_assign part of TRACE_EVENT(sctp_probe) to avoid the nest of entry function, and trigger sctp_probe_path_trace in sctp_outq_sack. After this patch, you can enable both events individually, # cd /sys/kernel/debug/tracing # echo 1 > events/sctp/sctp_probe/enable # echo 1 > events/sctp/sctp_probe_path/enable Or, you can enable all the events under sctp. # echo 1 > events/sctp/enable Signed-off-by: Kevin Kou Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/trace/events/sctp.h | 9 --------- net/sctp/outqueue.c | 6 ++++++ 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/include/trace/events/sctp.h b/include/trace/events/sctp.h index 7475c7be165aa..d4aac34365955 100644 --- a/include/trace/events/sctp.h +++ b/include/trace/events/sctp.h @@ -75,15 +75,6 @@ TRACE_EVENT(sctp_probe, __entry->pathmtu = asoc->pathmtu; __entry->rwnd = asoc->peer.rwnd; __entry->unack_data = asoc->unack_data; - - if (trace_sctp_probe_path_enabled()) { - struct sctp_transport *sp; - - list_for_each_entry(sp, &asoc->peer.transport_addr_list, - transports) { - trace_sctp_probe_path(sp, asoc); - } - } ), TP_printk("asoc=%#llx mark=%#x bind_port=%d peer_port=%d pathmtu=%d " diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index 7bb8e5603298d..d6e83a37a1adf 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -51,6 +51,7 @@ #include #include #include +#include /* Declare internal functions here. */ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); @@ -1257,6 +1258,11 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) /* Grab the association's destination address list. */ transport_list = &asoc->peer.transport_addr_list; + /* SCTP path tracepoint for congestion control debugging. */ + list_for_each_entry(transport, transport_list, transports) { + trace_sctp_probe_path(transport, asoc); + } + sack_ctsn = ntohl(sack->cum_tsn_ack); gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); asoc->stats.gapcnt += gap_ack_blocks; -- 2.25.1