From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4272A34CDD for ; Sat, 18 Oct 2025 00:16:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760746589; cv=none; b=dDCdLH6hQki5f1z0e7bvcegR5wynu2N6bSmY5aZ3euYIFtQeXl+RhrTH7O9+p+eQ6ZE+S5ukco3X2hdURRIeWSRX9nD2r1QAeTOh9Fw3WyxZd/Ji5webS97UcCYB17QJsIErdyVo1UJFrFAkn/ZMRCig3KtqEXvOvmQtu5fko7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760746589; c=relaxed/simple; bh=tffh3NT9wZET9SeG2m0qw3J5js+FrXIxuPgBPjXemzM=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=I7lgzH8X761kMjBQqHj/i5WWxGxT5UsCVJRO7mphcfT1cYIuAfQpjaHl5UyWF9SeNT4uX4nfuqeRtAXnye2l/8Ql5U/Y8B66VulxN/6N9OZCKYwWfCRbzCiQpQf2YXCJ4XtEkEjqBhnQGNpeOxM9D8MqgTX9TaMXLibk+J1BYMI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MDpPD8b8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MDpPD8b8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B3C5C4CEE7; Sat, 18 Oct 2025 00:16:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760746588; bh=tffh3NT9wZET9SeG2m0qw3J5js+FrXIxuPgBPjXemzM=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=MDpPD8b8syHlmdSJDp5lhgTfTbKBhaez1a4RqIToK2O1iFiVXFBTjTLoN3+uYSfAM 1BnLG4ajF9jdRQBhE/rKW1kWHOuS5qe4kZSv7shKNzHaNOWZfz7VSojNEJslBvUjbm 63HyAdPEyHdTy1EuAu2nG/gsxz8b26kAcOXs/DfgubuH5YxW4MHojynpNnvazCV3nS MSx1jvT5Zj7Q0UHLk0ejh8XAJFLUmSgAf3Uq6iVRHluyw33y+4+yGdjbQq0jcHkfxK Arjk9uJVAiIN2b9jsNmFjRBDP1oOa2mlRQtt8ze2Vm2S/8kcGGhLWj0qE03RdJO2CQ khR7sI1a1f7Zw== Date: Fri, 17 Oct 2025 17:16:27 -0700 (PDT) From: Mat Martineau To: Geliang Tang cc: Paolo Abeni , Matthieu Baerts , mptcp@lists.linux.dev Subject: Re: [PATCH v5 mptcp-next 00/10] mptcp: introduce backlog processing In-Reply-To: Message-ID: References: <2c9f131e-ef34-4916-8aab-e1420e1ae90b@kernel.org> <2389029f56a9fa496b59be7655987e6d9c6362f2.camel@kernel.org> <8a8feb1d-ad10-4ba4-a448-db8a0e45c7c3@redhat.com> <6d3545fc-f342-4532-b1c3-fb96d9c79fe6@redhat.com> <53ed629a-d364-470f-8a52-5a34692f0da7@redhat.com> <20a3df573803203df6b672d1ecd606e242e84b20.camel@kernel.org> <281e24d1-da6a-493e-9d12-66bd3cdd7ed4@redhat.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="0-570250240-1760746588=:34278" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-570250240-1760746588=:34278 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8BIT On Fri, 17 Oct 2025, Geliang Tang wrote: > Hi Paolo, Matt, Mat, > > On Wed, 2025-10-15 at 11:00 +0200, Paolo Abeni wrote: >> On 10/13/25 11:07 AM, Geliang Tang wrote: >>> On Fri, 2025-10-10 at 20:22 +0800, Geliang Tang wrote: >>>> Hi Paolo, >>>> >>>> On Fri, 2025-10-10 at 10:21 +0200, Paolo Abeni wrote: >>>>> On 10/9/25 3:58 PM, Paolo Abeni wrote: >>>>>> @Geliang: if you reproduce the issue multiple times, are >>>>>> there >>>>>> any >>>>>> common patterns ? i.e. sender files considerably larger than >>>>>> the >>>>>> client >>>>>> one, or only a specific subsets of all the test-cases >>>>>> failing, or >>>>>> ... >>>>> >>>>> Other questions: >>>>> - Can you please share your setup details (VM vs baremetal, >>>>> debug >>>>> config >>>>> vs non debug, vmg vs plain qemu, number of [v]cores...)? I >>>>> can't >>>>> repro >>>>> the issue locally. >>>> >>>> Here are my modifications: >>>> >>>> https://git.kernel.org/pub/scm/linux/kernel/git/geliang/mptcp_net-next.git/log/?h=splice_new >>>> >>>> I used mptcp-upstream-virtme-docker normal config to reproduce >>>> it: >>>> >>>> docker run \ >>>> -e INPUT_NO_BLOCK=1 \ >>>> -e INPUT_PACKETDRILL_NO_SYNC=1 \ >>>> -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it >>>> \ >>>>         --pull always ghcr.io/multipath-tcp/mptcp-upstream- >>>> virtme- >>>> docker:latest \ >>>> auto-normal >>>> >>>> $ cat .virtme-exec-run >>>> run_loop run_selftest_one ./mptcp_connect_splice.sh >>>> >>>> Running mptcp_connect_splice.sh in a loop dozens of times should >>>> reproduce the test failure. >>>> >>>>> - Can you please share a pcap capture _and_ the selftest text >>>>> output >>>>> for >>>>> the same failing  test? >>> >>> The pcap captures (gQQ13x-ns1-ns3-MPTCP-MPTCP-dead:beef:3::2-10013- >>> connector.pcap, gQQ13x-ns1-ns3-MPTCP-MPTCP-dead:beef:3::2-10013- >>> listener.pcap) and the selftest text output (selftest_output) are >>> attached. >> >> Looks like the 'stuck' scenario is quite consistent. The receiver >> filled >> it's receive window, and sent an ack shortly after when re-opening, >> but >> the sender did not react to such ack. >> >> The perf instrumentation I mentioned would be very useful. I tried to >> capture it myself, but so far I failed - the repro run for several >> hundred iterations without issues and finally podmad stuck (podman >> bug >> apparently, or local resources exhausted). >> >> Did you have better luck collecting the perf trace? > > Sorry, I haven't made any progress yet. Please give me some more time. > > > I was thinking, since this issue only occurs during the splice test, > let's move the discussion to the future "implement mptcp read_sock and > splice" series. We shouldn't let it block the merging of this current > series. > > I don't have any further constructive review comments on patches 9 and > 10. I'm wondering if we should get input from Matt and Mat. > I am planning to take a close look at 9 & 10 early next week, would like to understand the new backlog rx path. Sorry for the delay! - Mat --0-570250240-1760746588=:34278--