From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B8983E51F5 for ; Wed, 5 Aug 2026 08:22:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785918147; cv=none; b=afn+05KK2+vNI4mj7SrlmKT4ln3WZW27P5lcTYcce/IciFcrCqUm93MZRsNwrEu+O36L2ZYQQQWDcFApWFUz9pAZQPJHF/nMNhVmZh8yosZVLUoC3ZemKPXE81GPi8DuRNU1GcUNyiUbDhxOv8jpe9vntotaW4OPnnPCLvbwKa8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785918147; c=relaxed/simple; bh=QHYfGuMolQ8A3YO3Jr6H088OtOknOcMyY41/gK6OrmU=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gNYVJrlJNKT/pa/S3knfB3zz6h/lQ7ZSqDrlK17d+SZffy/FFTt7UaExOBQGrVIiqyoM3qNzu5D4pXwWwX9BXvkT/iGQdqxxOo4OPsVLUYrqWwuNHQrnk1Za5GKfSYRtb7Ejyhm393zlMBWdEL7Ea//3zBMMDZ4ZIbF9XoYaxPo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=U5XVSPn5; arc=none smtp.client-ip=209.85.221.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="U5XVSPn5" Received: by mail-wr1-f50.google.com with SMTP id ffacd0b85a97d-476a130c138so626320f8f.0 for ; Wed, 05 Aug 2026 01:22:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785918144; x=1786522944; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:to:from:date:from:to:cc:subject:date :message-id:reply-to:content-type; bh=QTnN+TvzBg4AjKqbGE7dFy9XV+JzEvnALTtq5MKiwe4=; b=U5XVSPn5x2NOpvbxG5Y4MS3/Mu1Wr/pqqkBPSbq/68HEWhDnikxR1GdK5NnZfRDT2s sL+wvmGm+H1FmecySVa2CBL/C2an+CR67Dk52cauAq7qGPU1XgLIJHqav5zlEqYbZy27 KbqJNxlBHMqnkx1ajOOWJnFws0KZrWTFAZpke9a0vVVs9DwRoevXRi9FNGWI2eSzENh1 tm0cTpExIi99tUbRBrwoSSCo+dMYUS46zQNoByFSQKWQH4ycHs23IlqJADuv0lg8WXEf HNN0rylmS754BnlHhUzdYQXVaFlyf+o7qO6+yq3w23E657ooYA+Ut1e20Se2GvM2GB1N ajLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785918144; x=1786522944; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=QTnN+TvzBg4AjKqbGE7dFy9XV+JzEvnALTtq5MKiwe4=; b=bDxobMGat9zNiRXMHKO8yN+7GbxuMlgMxYe4GIUhksNvTnL6mJNkmD6U+jo3T7KAOR AKu9OA6lQD312o5ym1h1xKcKxEOv4vx0PPT+Iyi+nhQpqkSUzr7JsQ9ZGihL64wMydkg ONX5/1qBYQilDClPbbpo/jvt656pdNsK6CHWB3vHus2gDFd8xDMOyFFKOW/fkPt6H8Ie hl0Xuxcg52U47fZ17aGCzIXe9tgFZ+zxjoDWhH9d+DsReAqROvCFRHiOVrNpQLsITjST yxXNWsJfVhFlH74UgIAqg886YuG+svN1VznXhFmIy91KWQ5aVFRvSyZURqHETRsfHN5R ao/w== X-Forwarded-Encrypted: i=1; AHgh+Rop/3c4HYWecW3PgC9WM+a+Rykezrm3FrH1YazsYYpz+/Sz7kJNWUISmVc395ObQtIQ99Xp8e3kBnmfG1U=@vger.kernel.org X-Gm-Message-State: AOJu0YykQ/MdQILvzaXsALBOB1fMbBzIWaykYflgj4P5H85AwNaVaHgT dxaY2dnt5PSxlpJ5ORnKgVI1ApNkVERMfT5ur0/NEURFySAq0tMlydRe X-Gm-Gg: AR+sD104hb3IIGtKoqpt8DDz9zO3Mh8qtngSLMaiyqWWhLKIPHfKOGWNS9/jdvhehEr CREbjBXJKCG4xqI+ROms4uv2hLbqc4pctUCm697nrMngq2eNy2w8C52B2wnzU3cs5w5pABP6YCH nTFlhkWIHsDkwpgfy1xPXPQwKrlJxDfKKFQWHkEft8xE8gkJXBvFoIUjPHcEX/Nwz6zbB69pUZS tsX9jo5u7GsCZ2Iy8NH/+Zvg8uRD5Ykw7PyTg0S43+5w1VWKCIW/7J/7eXsQp/xWbsBJI0hk5fv dUrquMO+/P3fEUNcolygfIerU849UoVEpq6PmJlmjkd7N9Cr8K7Jqp9r2uvkG/LxR3fxOSbkZMA rHwGMkJ1wJjkIrXAzGCUxoVKqzGLQoLD+FCQpscIVBpVS2gdF+wvmuG5fEdrOVLYFHXaPtVShsO 9BQ1ivWJfXNK/31Jsxy4JwyJ51FsjL7Hwh3HRnccr+wrwOvu5nS8TySQ6jQ6TcozCW8qXEXFu2p 72Z+n6tEQdaXecQCi57pN9xKmHfSSvadVUi6gE0WKmiR/x5uxGI X-Received: by 2002:a05:6000:382:b0:476:7036:f854 with SMTP id ffacd0b85a97d-47fec52a21amr8100866f8f.21.1785918143400; Wed, 05 Aug 2026 01:22:23 -0700 (PDT) Received: from localhost.localdomain (host86-153-201-25.range86-153.btcentralplus.com. [86.153.201.25]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47febfe5d7csm7233885f8f.15.2026.08.05.01.22.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Aug 2026 01:22:22 -0700 (PDT) Date: Wed, 5 Aug 2026 09:22:20 +0100 From: Nnamdi Onyeyiri To: bpf@vger.kernel.org, davem@davemloft.net, edumazet@google.com, horms@kernel.org, jakub@cloudflare.com, jiayuan.chen@linux.dev, john.fastabend@gmail.com, kuba@kernel.org, kuniyu@google.com, ncardwell@google.com, netdev@vger.kernel.org, pabeni@redhat.com, sashiko-reviews@lists.linux.dev, linux-kernel@vger.kernel.org, emil@etsalapatis.com Subject: Re: [PATCH v7 0/2] bpf, sockmap: handle spurious tcp_msg_wait_data() wakeup Message-ID: References: <20260721223807.75101-1-nnamdio@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260721223807.75101-1-nnamdio@gmail.com> On Tue, Jul 21, 2026 at 11:38:05PM +0100, Nnamdi Onyeyiri wrote: > Spurious wakeups in tcp_msg_wait_data() aren't being handled by > tcp_bpf_recvmsg() and tcp_bpf_recvmsg_parser(), leading to unexpected > EAGAIN errors returned by recvfrom()/recv(). Adding handling for the > wakeup and a selftest. > > This issue was first discovered in an application that adds sockets to > a sockmap as a way to view the received data. No redirects or any > other operations are performed. > > Sashiko has noted a few other pre-existing issues in the same area > (https://patch.msgid.link/20260714205118.17DB11F000E9@smtp.kernel.org) > that can lead to EAGAIN in tcp_bpf_recvmsg() and > tcp_bpf_recvmsg_parser(). A local run of Sashiko also identified a > potential issue in tcp_bpf_recvmsg() handling zero-data FIN packets when > the MSG_PEEK flag is set. To prevent this patchset from growing too > large, I intend to submit follow up patches to address these once this > one has been accepted. > > Changes in v7: > - In tcp_bpf_recvmsg check for data in the TCP_CLOSE, !timeo and > signal_pending branches. > - Refactored changes to tcp_bpf_recvmsg to reduce duplication. > - Increase the number of iterations in the selftests. > - Documented selftests numeric constants. > - Link to v6: https://patch.msgid.link/20260720171535.67867-1-nnamdio@gmail.com > > Changes in v6: > - Closing the file descriptor in the selftest worker thread. > - Ensuring the selftest loop breaks early for an error in the worker > thread. > - Added comments to selftest regarding focus on EAGAIN error. > - Updated selftest commit message to imperative mood. > - Link to v5: https://patch.msgid.link/20260717155348.54975-1-nnamdio@gmail.com > > Changes in v5: > - Move selftest from net into bpf/prog_tests/sockmap_basic.c > - Link to v4: https://patch.msgid.link/20260715213538.37229-1-nnamdio@gmail.com > > Changes in v4: > - Fix potential data loss in tcp_bpf_recvmsg() when a FIN or RST has > been received. > - Check the return code of pthread_create() in the selftest. > - Fix race caused by using EXPECT macros in a thread in selftest. > - Link to v3: https://patch.msgid.link/20260714203927.32289-1-nnamdio@gmail.com > > Changes in v3: > - Added the sockmap_recvfrom selftest. > - Link to v2: https://patch.msgid.link/alFRK66z45eDNZA7@localhost.localdomain > > Changes in v2: > - In tcp_bpf_recvmsg, handle signals and the socket closing in the loop. > - Fix spurious wakeups when SO_RCVTIMEO has been set on the socket. > - Link to v1: https://patch.msgid.link/ak_rR-Skd8Mvn4mH@localhost.localdomain > > Signed-off-by: Nnamdi Onyeyiri > --- > Nnamdi Onyeyiri (2): > bpf, sockmap: handle spurious tcp_msg_wait_data() wakeup > selftests/bpf: add sockmap recvfrom EAGAIN selftest > > net/ipv4/tcp_bpf.c | 72 ++++++++-- > .../selftests/bpf/prog_tests/sockmap_basic.c | 136 ++++++++++++++++++ > 2 files changed, 199 insertions(+), 9 deletions(-) > > -- > 2.52.0 > Hi all, just wondering if you need anything more from me on this?