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 70930264F81; Thu, 13 Nov 2025 15:20:01 +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=1763047202; cv=none; b=t+5ZIvc1yJxuD3ua+Dk2TlijkaGcufZoyORnd2QZGHIUB7NbTmkS0srNge638AWLQxcmSNafFAvSty07HPp5pVmGWHYm6Led0g640COMXLuyaNwsNQMVqdQM6eQW63WoRkHihZIG9GpIyg+C9KG/gRZ28zZmxdyY1Sie3JwvBO8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763047202; c=relaxed/simple; bh=lWYhbavprkT3U9nZXKkesHRb9Y0PC/NemTNV0+uAcaI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=diq56RwR5JZfROGbNKRG889MWFFFpZFTj5O5WV4S6VhqhhPBNA3A7UZvrrb9rR6xG6vSV+LfKpgSOhPkIW6uEr4BaTopRlkcWB9sPNpWrPacSVkKUnoGKm72gye5NiFHhhRwcOUFwRWO/rd//TFD0QA3BBuGsnFzivxoucYwIqI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mRrfucok; 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="mRrfucok" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8D70C4CEF8; Thu, 13 Nov 2025 15:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763047200; bh=lWYhbavprkT3U9nZXKkesHRb9Y0PC/NemTNV0+uAcaI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mRrfucok2Ntrq4u+nF5na/T140QwG94RXgPIwX81QtT+ro5IOP+JfWj4ExGTKDhpx wibxCg+MXTvxezSyilx4YcnEUl2nrVNiPe0S9TRcCabAdRp2o4l0XpB3/XSFwmQgpc OfGQDutQ0FPEm3b+75eM7/OZggIfuz5PrXnZrG0zhRu89IPTeTdwLcPNwQtZdS4m6Y uh69YNf6UlBqJwMCeehbf0UJfQTBW9KehJICFpyKw//SpnF7iYLLlHwKYQ8dCruXjp SqVxdSx0xRmCyuqQtXtN9vxctyv7x44xuJlmat8klBW7nZ2h8WHWu86CjwzF6UySbt W4hSuuf6dyNWQ== Message-ID: <48bbe998-982c-4dbd-b261-83c076ebcb7a@kernel.org> Date: Thu, 13 Nov 2025 16:19:56 +0100 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: Patch "mptcp: drop bogus optimization in __mptcp_check_push()" has been added to the 5.15-stable tree Content-Language: en-GB, fr-BE To: gregkh@linuxfoundation.org, sashal@kernel.org Cc: stable-commits@vger.kernel.org, geliang@kernel.org, kuba@kernel.org, martineau@kernel.org, pabeni@redhat.com, "stable@vger.kernel.org" , MPTCP Linux References: <2025110310-scapegoat-magnetic-3cf8@gregkh> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: <2025110310-scapegoat-magnetic-3cf8@gregkh> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Greg, Sasha, On 03/11/2025 02:38, gregkh@linuxfoundation.org wrote: > > This is a note to let you know that I've just added the patch titled > > mptcp: drop bogus optimization in __mptcp_check_push() > > to the 5.15-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > mptcp-drop-bogus-optimization-in-__mptcp_check_push.patch > and it can be found in the queue-5.15 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let know about it. Can you please drop this patch from v5.15? It looks like it is causing some issues with MP_PRIO tests. I think that's because back then, the path is selected differently, with the use of 'msk->last_snd' which will bypass some decisions to where to send the next data. I will try to check if another version of this patch is needed for v5.15. Cheers, Matt (I kept the patch below just in case some people from the MPTCP ML want to react.) > From stable+bounces-192087-greg=kroah.com@vger.kernel.org Mon Nov 3 05:15:58 2025 > From: Sasha Levin > Date: Sun, 2 Nov 2025 15:15:50 -0500 > Subject: mptcp: drop bogus optimization in __mptcp_check_push() > To: stable@vger.kernel.org > Cc: Paolo Abeni , Geliang Tang , Mat Martineau , "Matthieu Baerts (NGI0)" , Jakub Kicinski , Sasha Levin > Message-ID: <20251102201550.3588174-1-sashal@kernel.org> > > From: Paolo Abeni > > [ Upstream commit 27b0e701d3872ba59c5b579a9e8a02ea49ad3d3b ] > > Accessing the transmit queue without owning the msk socket lock is > inherently racy, hence __mptcp_check_push() could actually quit early > even when there is pending data. > > That in turn could cause unexpected tx lock and timeout. > > Dropping the early check avoids the race, implicitly relaying on later > tests under the relevant lock. With such change, all the other > mptcp_send_head() call sites are now under the msk socket lock and we > can additionally drop the now unneeded annotation on the transmit head > pointer accesses. > > Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") > Cc: stable@vger.kernel.org > Signed-off-by: Paolo Abeni > Reviewed-by: Geliang Tang > Tested-by: Geliang Tang > Reviewed-by: Mat Martineau > Signed-off-by: Matthieu Baerts (NGI0) > Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-1-38ffff5a9ec8@kernel.org > Signed-off-by: Jakub Kicinski > [ split upstream __subflow_push_pending modification across __mptcp_push_pending and __mptcp_subflow_push_pending ] > Signed-off-by: Sasha Levin > Signed-off-by: Greg Kroah-Hartman > --- > net/mptcp/protocol.c | 13 +++++-------- > net/mptcp/protocol.h | 2 +- > 2 files changed, 6 insertions(+), 9 deletions(-) > > --- a/net/mptcp/protocol.c > +++ b/net/mptcp/protocol.c > @@ -1137,7 +1137,7 @@ static void __mptcp_clean_una(struct soc > if (WARN_ON_ONCE(!msk->recovery)) > break; > > - WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); > + msk->first_pending = mptcp_send_next(sk); > } > > dfrag_clear(sk, dfrag); > @@ -1674,7 +1674,7 @@ void __mptcp_push_pending(struct sock *s > > mptcp_update_post_push(msk, dfrag, ret); > } > - WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); > + msk->first_pending = mptcp_send_next(sk); > } > > /* at this point we held the socket lock for the last subflow we used */ > @@ -1732,7 +1732,7 @@ static void __mptcp_subflow_push_pending > > mptcp_update_post_push(msk, dfrag, ret); > } > - WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); > + msk->first_pending = mptcp_send_next(sk); > } > > out: > @@ -1850,7 +1850,7 @@ static int mptcp_sendmsg(struct sock *sk > get_page(dfrag->page); > list_add_tail(&dfrag->list, &msk->rtx_queue); > if (!msk->first_pending) > - WRITE_ONCE(msk->first_pending, dfrag); > + msk->first_pending = dfrag; > } > pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d\n", msk, > dfrag->data_seq, dfrag->data_len, dfrag->already_sent, > @@ -2645,7 +2645,7 @@ static void __mptcp_clear_xmit(struct so > struct mptcp_sock *msk = mptcp_sk(sk); > struct mptcp_data_frag *dtmp, *dfrag; > > - WRITE_ONCE(msk->first_pending, NULL); > + msk->first_pending = NULL; > list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) > dfrag_clear(sk, dfrag); > } > @@ -3114,9 +3114,6 @@ void __mptcp_data_acked(struct sock *sk) > > void __mptcp_check_push(struct sock *sk, struct sock *ssk) > { > - if (!mptcp_send_head(sk)) > - return; > - > if (!sock_owned_by_user(sk)) { > struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk)); > > --- a/net/mptcp/protocol.h > +++ b/net/mptcp/protocol.h > @@ -325,7 +325,7 @@ static inline struct mptcp_data_frag *mp > { > const struct mptcp_sock *msk = mptcp_sk(sk); > > - return READ_ONCE(msk->first_pending); > + return msk->first_pending; > } > > static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk) Cheers, Matt -- Sponsored by the NGI0 Core fund.