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[144.49.247.2]) by smtp-relay.gmail.com with ESMTPS id d75a77b69052e-5100da45bc1sm1364411cf.6.2026.04.28.02.24.20 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Apr 2026 02:24:21 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-dy1-f198.google.com with SMTP id 5a478bee46e88-2ed0934b410so109660eec.1 for ; Tue, 28 Apr 2026 02:24:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1777368260; x=1777973060; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=IzPOnX+4u79/JYJ7Z4oEDndQq0Exv1P8b4YAmspEcU4=; b=JgZASNicZYhFDPOEua8M8St8hIx6jLDc2TFrJdHtt9yfi7n8ZhbO8kB1v5HIgpZIzy C0qyUnqgwJHc2dm3DrRZKqIpcboCZ/EO8Ud//hMykpL0tJoAoV2QsHOE1p5xyjgcM8Ll D2Y0Vz8fZWjVCsdm3m3tP8N75U+d+9hYdYM0Y= X-Forwarded-Encrypted: i=1; AFNElJ/YcJkYBkVHyXbRGnkNe6tSi86muoE0f4m52ODJeKlt38/BAiMieqsNnvxPmrL+gaXq3oAS31EXLZbivzE=@vger.kernel.org X-Received: by 2002:a05:7300:d70d:b0:2c4:ec89:bdb with SMTP id 5a478bee46e88-2ed09a38a2bmr455064eec.2.1777368259653; Tue, 28 Apr 2026 02:24:19 -0700 (PDT) X-Received: by 2002:a05:7300:d70d:b0:2c4:ec89:bdb with SMTP id 5a478bee46e88-2ed09a38a2bmr455057eec.2.1777368258999; Tue, 28 Apr 2026 02:24:18 -0700 (PDT) Received: from photon-d7fac424c0d3 ([192.19.161.250]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ed09fd6e19sm1666250eec.13.2026.04.28.02.24.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2026 02:24:18 -0700 (PDT) From: Ankit Jain To: kuba@kernel.org Cc: netdev@vger.kernel.org, edumazet@google.com, ncardwell@google.com, kuniyu@google.com, davem@davemloft.net, dsahern@kernel.org, pabeni@redhat.com, horms@kernel.org, quic_stranche@quicinc.com, quic_subashab@quicinc.com, linux-kernel@vger.kernel.org, karen.badiryan@broadcom.com, ajay.kaher@broadcom.com, alexey.makhalov@broadcom.com, vamsi-krishna.brahmajosyula@broadcom.com, yin.ding@broadcom.com, tapas.kundu@broadcom.com Subject: Re: [PATCH net] tcp: do not shrink window clamp when SO_RCVBUF is locked Date: Tue, 28 Apr 2026 09:21:10 +0000 Message-ID: <20260428092110.2280-1-ankit-aj.jain@broadcom.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260427131111.168ed0dc@kernel.org> References: <20260427131111.168ed0dc@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e Hi Jakub, Thank you for pointing this out. I checked the logic again, I placed the SOCK_RCVBUF_LOCK check on the outer if-statement. This successfully prevented tcp_set_window_clamp() from crushing the window (fixing the Java SWS bug), but it accidentally bypassed the tp->rcvq_space.space bounds check as well. Because of this, the receive queue tracking got out of sync when the test hit a negative window. For v2, I will move the lock check inside the block so it only bypasses tcp_set_window_clamp(), ensuring the rcvq_space.space limits still execute as expected. I will test the refined logic against my reproducer and the tcp_rcv_neg_window.pkt script locally, and I will post the v2 series in a new thread after the 24-hour cooldown. Thanks, Ankit