From nobody Thu Dec 18 13:26:50 2025 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 8D3D523C385 for ; Tue, 18 Feb 2025 11:24:56 +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=1739877896; cv=none; b=hksSmmYx3+3eCcEdnf2VOsnHd1+JnKWi+rw8OVlatGF8TFEkBcF4HuPK05J1FjHnVPzEEIc/Vz+0Oj1f8caN+G6IqzOsxHoMGVgw7VLlqlkOLtT50wxtQlLtdROiIKGhDN2w9PHrT8QzEcL5Yb/2mMzEopGSQs8SKQeUnKrQCwE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739877896; c=relaxed/simple; bh=jTQZdhnD4SDNeCdoABo6+2QrCmcs9b2jVmYynAo2Rew=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=FxQtrBBQVo6BfAbFvrYMqbgFeqrXXV1N7ycQAqqjYFt7u1qnKinFqK1lR4k0R7QimQQJ3fNW5ZF/2zIk4t97LaF/nWXNYQUDQRacLjPauBotovddYgPxdiEGcJFsPFHYfzU5b9QW+SAABBXDe+T/t2vBqRssjwomsakyjMf46NA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=POAFnaPm; 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="POAFnaPm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71072C4CEE9; Tue, 18 Feb 2025 11:24:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739877896; bh=jTQZdhnD4SDNeCdoABo6+2QrCmcs9b2jVmYynAo2Rew=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=POAFnaPmR7c9b7lVDfJMNdSpiZhoStUJL7pppL/JUiI64ln+lvDqWldsNkSDa5Gmg kWNR3fvy9mQXtGyFHogE4nqPFEmMxUIp/Bad8xlyXxe5NCO5HQZgeEIFsswJ9CdFyL J1cS5rub6g1gLxArYdAafdhlb9JKVDZhK3Hf77/IZUPM6wf6AQvNV+qqwfzsy8U0mP q//70Lrc4TrW15JgfBXViThKJbzTSyB/ZS1SjjxrxPqYyY9lSgxMHB3evglLP4ndZO Os0yO+vK/1YtjjU7yjc0ysg5231EaXT61mVlkgk00Uk/zbP68gSJa2cexAAh7wWKlf lnprL8aiGdcyQ== From: "Matthieu Baerts (NGI0)" Date: Tue, 18 Feb 2025 12:24:47 +0100 Subject: [PATCH mptcp-net v2 2/2] mptcp: safety check before fallback Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250218-mptcp-dss-drop-mpj-v2-2-0c6caa10ec52@kernel.org> References: <20250218-mptcp-dss-drop-mpj-v2-0-0c6caa10ec52@kernel.org> In-Reply-To: <20250218-mptcp-dss-drop-mpj-v2-0-0c6caa10ec52@kernel.org> To: mptcp@lists.linux.dev Cc: Paolo Abeni , "Matthieu Baerts (NGI0)" X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1126; i=matttbe@kernel.org; h=from:subject:message-id; bh=jTQZdhnD4SDNeCdoABo6+2QrCmcs9b2jVmYynAo2Rew=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBntG4ECHO0AaBZ4Jrq4J1Ygp/RkiwCVzSD0E0qt jEG67CIEMmJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZ7RuBAAKCRD2t4JPQmmg c162D/0Q5m2Qbp7knOJdRvobQGJ/rAUj2p3nRvnpNSpo+5greiGf9ZpVKiQzKu9SusOJbltQJhf UgvbsR4irNVAmgoZ+LPFGAhgjea84PFOxcUWsimGd63u9g7GLw76fkf1HS1H5ochgba8yLyo0nz X8Q1+UJTMMTwAToDVZRfxObjoNbHLsKZHMwtKYXtBg4vJbLWRhqGf2ZjEKBbobP1HpART+rWKOc u4HiL8kQNQkzdjNnND5vf1K4dByr0aKOyvqZf/AWAfffOm0OV0unuMicnV/2Eh9Pa8DId05XpHE nkCk/BET40vTartApv+mzMHg/wvdGH4LiVIJUrHyVsCLQJx79P+lD1dk1egwBOTSGMqYjm/N8x+ o6TW/LEtVKpMsSGNB2gw0OEvamAapAlYRsPaZfnCdtZiCOBQm+oSsqFbWWF1bHtVdsTwTA/hIXA QmFryfd6PdR0sl+jR6RMCoDq9sVMQBzWrYIC7YtynwC2d+phkp86gpWrMK2eXHerGuKYD7iY0rh uuGdJENZdGlt/Tf1GTwmUBZjgzQxdDlb9kAiEuqRss5zNLrf9YrHfVt0gak/ofvj56b1T2sdt18 mbKsgweAgVWCislT9jrKcGwVwrl3gdvO1BumQ5utpnhZwXYlbqX2bxvJitco3Dfq3O5YdX13Cqw WdwcC5a+U6sy+ag== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Recently, some fallback have been initiated, while the connection was not supposed to fallback. Add a safety check with a warning to detect when an wrong attempt to fallback is being done. This should help detecting any future issues quicker. Signed-off-by: Matthieu Baerts (NGI0) --- Notes: - I guess this patch could be sent to -net as well. - We could also squash this in one of the previous commit, but because the two are needed to avoid the warning, maybe better with a dedicated commit? --- net/mptcp/protocol.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index bac5c925a72f6637e33ada9869984c5902bd6a43..3d72ca1553227cb41ba8c205f42= d1f01cc264a7e 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -1198,6 +1198,8 @@ static inline void __mptcp_do_fallback(struct mptcp_s= ock *msk) pr_debug("TCP fallback already done (msk=3D%p)\n", msk); return; } + if (WARN_ON_ONCE(!READ_ONCE(msk->allow_infinite_fallback))) + return; set_bit(MPTCP_FALLBACK_DONE, &msk->flags); } =20 --=20 2.47.1