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 F1BF919CCFA; Mon, 3 Mar 2025 17:05:17 +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=1741021518; cv=none; b=V9kJl6XzvYjrWJeAHRuB9abDwjXqk8OpCp2WoWS79cXLQrJluhBQf0sXCWzozs78iLtTW2oGKTSw8RLc0CaOYPBCaMYKZh42cVzCcvKZaInp2/tB4+lsQrfpZzMILcGf8ESgE7aHSVdfSHBWOvHIrmUFV8+bO3itnRCFQAaNPeg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741021518; c=relaxed/simple; bh=TzOR+breRxvFtuumY7ruSSCMNyZ5qObZIA5LHjdgkFc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=st8M6M4RiFhI3TYTyALV+t2oF1Ss7sXVbLCK/aWDheUcOCWdeT/YykC88isfsMFPo0XhShmUqP2uzQm7AwTpIujuwm+6xOeH180YjWCZ2bmyNwYKxkvB51QSbwRJ9ePzdtzLlXJT8b3mA9Hl2GF4hqQh3y/eCVFXmKFq+o+SOpg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PBzZYfLJ; 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="PBzZYfLJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1F74C4CED6; Mon, 3 Mar 2025 17:05:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741021517; bh=TzOR+breRxvFtuumY7ruSSCMNyZ5qObZIA5LHjdgkFc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PBzZYfLJum+TzfzM9TnOyznlC/2JJ9gpDm2gVHvubxPlZ85IsQE5JLJmjD/52l2PS lDH4mDwXCLR1C9sHTHvtH12E5iFYjfH7kj+FD8kABdkCFgS7DIT7XPxM2jNxvx7kFo T7JcwUDcmmAFjOUZNMvSKOUwb17PknlKlSlyOL7ecV9zBk5uMUO/Lpm6c4KzX3essA 2nb8oguQe8PtFfpb3J5XhRrvGklfTazZg5fFfxsRs+pdPAa2k8XpW55dk5FL7qaLi1 CnMeCn0pXK/gXUhVltzEvcsfQ5d+jFAJEDwsMeF3HHD0AZqjwHwdPCq8jgSc7Z+b1x cbKu0rrxnjnvg== Message-ID: <262b5990-47e8-44f9-a2af-ca9c389e34fd@kernel.org> Date: Mon, 3 Mar 2025 18:05:12 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH AUTOSEL 6.13 13/17] mptcp: safety check before fallback Content-Language: en-GB To: Sasha Levin , linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Paolo Abeni , Jakub Kicinski , martineau@kernel.org, davem@davemloft.net, edumazet@google.com, netdev@vger.kernel.org, mptcp@lists.linux.dev References: <20250303162951.3763346-1-sashal@kernel.org> <20250303162951.3763346-13-sashal@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Sasha, On 03/03/2025 17:29, Sasha Levin wrote: > From: "Matthieu Baerts (NGI0)" > > [ Upstream commit db75a16813aabae3b78c06b1b99f5e314c1f55d3 ] > > 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. > > Acked-by: Paolo Abeni > Signed-off-by: Matthieu Baerts (NGI0) > Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-3-f550f636b435@kernel.org > Signed-off-by: Jakub Kicinski > Signed-off-by: Sasha Levin Thank you for backporting this patch, but is it OK to delay it a bit on v6.13 and older please? This patch depends on its parent commit, commit 8668860b0ad3 ("mptcp: reset when MPTCP opts are dropped after join"), on kernels >=v5.19, to avoid a WARN(). > diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h > index b70a303e08287..7e2f70f22b05b 100644 > --- a/net/mptcp/protocol.h > +++ b/net/mptcp/protocol.h > @@ -1194,6 +1194,8 @@ static inline void __mptcp_do_fallback(struct mptcp_sock *msk) > pr_debug("TCP fallback already done (msk=%p)\n", msk); > return; > } > + if (WARN_ON_ONCE(!READ_ONCE(msk->allow_infinite_fallback))) An alternative is to drop the WARN_ON_ONCE() when backporting this to stable, and only keep the condition here: if (!READ_ONCE(msk->allow_infinite_fallback)) > + return; > set_bit(MPTCP_FALLBACK_DONE, &msk->flags); > } > Cheers, Matt -- Sponsored by the NGI0 Core fund.