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Mon, 01 Jun 2026 00:17:40 -0700 (PDT) Received: from [192.168.88.32] ([169.155.232.197]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4909d7002e8sm254530635e9.15.2026.06.01.00.17.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 01 Jun 2026 00:17:39 -0700 (PDT) Message-ID: <5ec7e9c4-6985-4582-b0d0-124d3ff568e1@redhat.com> Date: Mon, 1 Jun 2026 09:17:39 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mptcp-net] mptcp: fix uninit-value in mptcp_established_options To: Matthieu Baerts , mptcp@lists.linux.dev References: From: Paolo Abeni In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: UlWAMrwWIHhzruYpL_rzek4bHUD17p11AAfE_sUVSRw_1780298261 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/1/26 4:42 AM, Matthieu Baerts wrote: > Hi Paolo, > > On 29/05/2026 19:13, Paolo Abeni wrote: >> syzbot reported the following uninit splat: >> >> ===================================================== > > (...) > >> ===================================================== >> >> The output path currently omit initializing the mptcp extension `use_map` >> flag in a few corner cases. >> Address the issue always zeroing all the extensions flags before >> eventually initializing the individual bits. To that extent, introduce >> and use a struct_group to avoid multiple bitwise operations. >> >> Reported-by: syzbot+ff020673c5e3d94d9478@syzkaller.appspotmail.com >> Closes: https://syzkaller.appspot.com/bug?extid=ff020673c5e3d94d9478 >> Fixes: 6d0060f600ad ("mptcp: Write MPTCP DSS headers to outgoing data packets") > > Small detail: I hope that's OK to use this one instead: > > cfcceb7a39fc ("tcp: shrink per-packet memset in __tcp_transmit_skb()") > > Before this commit, the whole "opts" was set to 0. So no need to > backport this "too far". Sure, thanks for doing the right archeology! /P