From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4C18D3FF8B9 for ; Tue, 25 Aug 2026 11:51:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787658697; cv=none; b=QvpLzMVLlh11c9wxWGfmg8dBLUc1Fk5ZUzX587rpx34BOaaDAookQQJvzl8yMzySyXVLTWshsMhW1LloDbo03bTnOnaZ3MtMTxmRd6Mns53WsbIRbQGYXOGIAVZMNlJJUP0agrEnTz5nuMQiHmCumAC5WbIsXfysav5uzl71IXg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787658697; c=relaxed/simple; bh=D+9jb6pYfsvxF1DulPcojSNorTX7TSyP2zjYUqgG4/o=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=Wz5fMsJ6rNhYztja+RgN2k5bnUxOKgcmASW6KACcsqdxekIWNz6t8e/NwgepLIoc/QXZI/o+R+Kb83KfRFtZ2QqHcm3C8A7Z6VUfWs6poxG8IaUGPltphTEAXIXiB36eCH4s4fsNBCcXrcFv+yuoWiZh0ck6ufe+6PE9yPqOul4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jcmoYtFc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jcmoYtFc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B746F1F000E9; Tue, 25 Aug 2026 11:51:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787658695; bh=SoJ9PxZLfYf7CiApKG+sk5+gohT7eAN8Og+lJzH9Ivo=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=jcmoYtFcd0vE9vJ15D0WDBXmV0sBpw3/km7kpp8Z8w++N6RVKuIebeXArz5Uf4ofb uebwPano2wD1wTCrv6b0VE84paSYUlrdFzbDNaVKA0tBTiRjEEU3E4yJc0+D8I5g8k l85lBxhmYhb1zGaXK/l0s+7kI6rFFW7vhmLI8GeivCtP6E6nv+fS+zKn8CtUKWzEaq b1mofxUnthnGrheoJX3lJDr/hfWC4yrWQCQO9j21X71PeKkMDd4J9xOFyRgK9Wbctw DtPYROW3HOhWlr6B1lK9j+diD7jnYKrHaBs2RtM7SyDEKaGehc/jPwTewMHK2fZ9WQ E/FFrcfSHeR7Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH net-next] mptcp: normalize seq numbers reported in mptcp_info Reply-To: sashiko-reviews@lists.linux.dev To: "Kalpan Jani" Cc: mptcp@lists.linux.dev In-Reply-To: <20260825113355.3573376-1-kalpan.jani@mpiricsoftware.com> References: <20260825113355.3573376-1-kalpan.jani@mpiricsoftware.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 25 Aug 2026 11:51:35 +0000 Message-Id: <20260825115135.B746F1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] Asymmetric normalization of local and remote sequence numbers cr= eates an off-by-one inconsistency in MPTCP_INFO. -- --- Patch [1]: [PATCH net-next] mptcp: normalize seq numbers reported in mp= tcp_info --- commit 6231029f4c06cd4480ab1f97fc9151acd4862390 Author: Kalpan Jani mptcp: normalize seq numbers reported in mptcp_info This commit normalizes the sequence numbers reported by mptcp_info. It caches the local and remote initial sequence numbers and subtracts them in mptcp_diag_fill_info() so the diagnostic fields start near 0. Link: https://github.com/multipath-tcp/mptcp_net-next/issues/445 > diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c > index fcf6feb2a9eb5..0468099b19bfc 100644 > --- a/net/mptcp/sockopt.c > +++ b/net/mptcp/sockopt.c [ ... ] > @@ -1010,7 +1010,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, s= truct mptcp_info *info) > slow =3D lock_sock_fast(sk); > info->mptcpi_csum_enabled =3D READ_ONCE(msk->csum_enabled); > info->mptcpi_token =3D msk->token; > - info->mptcpi_write_seq =3D msk->write_seq; > + info->mptcpi_write_seq =3D msk->write_seq - msk->local_idsn; > info->mptcpi_retransmits =3D inet_csk(sk)->icsk_retransmits; > info->mptcpi_bytes_sent =3D msk->bytes_sent; > info->mptcpi_bytes_received =3D msk->bytes_received; [ ... ] > @@ -1024,8 +1024,8 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, s= truct mptcp_info *info) > =20 > mptcp_data_lock(sk); > info->mptcpi_last_ack_recv =3D jiffies_to_msecs(now - msk->last_ack_rec= v); > - info->mptcpi_snd_una =3D msk->snd_una; > - info->mptcpi_rcv_nxt =3D msk->ack_seq; > + info->mptcpi_snd_una =3D msk->snd_una - msk->local_idsn; > + info->mptcpi_rcv_nxt =3D msk->ack_seq - msk->remote_idsn; > info->mptcpi_bytes_acked =3D msk->bytes_acked; > mptcp_data_unlock(sk); > } > diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c > index af81ad5e699d1..4fa19835c4055 100644 > --- a/net/mptcp/subflow.c > +++ b/net/mptcp/subflow.c > @@ -465,6 +465,7 @@ void __mptcp_sync_state(struct sock *sk, int state) > * even for the FASTOPEN scenarios > */ > WRITE_ONCE(msk->write_seq, subflow->idsn + 1); > + WRITE_ONCE(msk->local_idsn, subflow->idsn); > WRITE_ONCE(msk->snd_nxt, msk->write_seq); > mptcp_set_state(sk, state); > sk->sk_state_change(sk); [ ... ] > @@ -491,6 +492,7 @@ static void subflow_set_remote_key(struct mptcp_sock = *msk, > =20 > WRITE_ONCE(msk->remote_key, subflow->remote_key); > WRITE_ONCE(msk->ack_seq, subflow->iasn); > + WRITE_ONCE(msk->remote_idsn, subflow->iasn); [Severity: Medium] Will this result in an asymmetric baseline where mptcpi_write_seq and mptcpi_snd_una start at 1, while mptcpi_rcv_nxt starts at 0? Looking at subflow_set_remote_key(), subflow->iasn is incremented before it= is assigned to msk->remote_idsn: mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn); subflow->iasn++; However, in __mptcp_sync_state(), msk->local_idsn is assigned the unincreme= nted subflow->idsn: WRITE_ONCE(msk->write_seq, subflow->idsn + 1); WRITE_ONCE(msk->local_idsn, subflow->idsn); When these are subtracted in mptcp_diag_fill_info(), msk->write_seq (which = is subflow->idsn + 1) minus msk->local_idsn results in 1, while msk->ack_seq m= inus msk->remote_idsn results in 0. Should msk->local_idsn and msk->remote_idsn both use either the incremented= or unincremented hash to ensure the normalized sequences start at the same val= ue? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260825113355.3573= 376-1-kalpan.jani@mpiricsoftware.com?part=3D1