From nobody Sat Jul 25 01:37:30 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) (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 B9B4A400990; Tue, 21 Jul 2026 02:26:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784600775; cv=none; b=qIwEK/AQ9If1Lk6RXiSXyYyilBXyPfBAxePhfZxDKiNCv/opfMl1Q48tRpo/zy4alrmYXSDyDMh4DBcwwP3zQfZHVo94Tx8+SUwDMnZdM3D09s0QXYnYzOMRUNRbIfNaMxEPV1BHd66bclabSOlVvjEYm4cZIW98cbMIoqqtceM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784600775; c=relaxed/simple; bh=csN9nc/Fk+W9/o7VXwUrKsqPz6/xdMK1DSx/2jIVHnE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=aUw0Ez/4FThcSKk9hQggpEtr6DEUHnorIts1AC+tqlrnZ8nBJ65mE1Oe3CkhhwkQOqXq8mTvkb9wrlfQniKCeuJq6ZRSffaixMzyoVcj2yj9onphpX0huAfTsrxQM89otHoEOXQblHWFxwqmyCG1+LO4Fn4oGRviKTCWcblXR3g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=g2VsBu7S; arc=none smtp.client-ip=220.197.31.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="g2VsBu7S" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version: Content-Type; bh=x0IcHSv9W/Yq+myep3UwQEGkRffz0hgPt6rbcqKY/08=; b=g2VsBu7SmDy8WeYwYKwS2mH/213ybJTzRmzKKmnVoUNPjz35vUHuTA3l64mtpp I+4cULj3sRkF4xvVNV28yOLhcTppFD8cXlr5ggIYBg6SFBhKHXiMpGHUMFtj3/pq VIJDMVflAHqPgUDHkHprfhqgrP/e4luvWwpVuElivveG8= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wA3wpOS2F5q9u4KLA--.38248S2; Tue, 21 Jul 2026 10:25:24 +0800 (CST) From: luoqing To: marcelo.leitner@gmail.com, lucien.xin@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: horms@kernel.org, linux-sctp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v4] sctp: socket: set *err = 0 on receive shutdown Date: Tue, 21 Jul 2026 10:25:22 +0800 Message-Id: <20260721022522.178618-1-l1138897701@163.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wA3wpOS2F5q9u4KLA--.38248S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7uF4rtr15AF4kZFy5AryxZrb_yoW8AF47pr 4xCF4DJrWkJry8ZFs7KF4xJ3W5K395Aw4fAayUWw4akrs8GF98Kw15tF1akF17uF4rWay0 vr1qq3W3W3WkuFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07Uq-erUUUUU= X-CM-SenderInfo: jorrjmiyzxliqr6rljoofrz/xtbC3hSN0Wpe2JRCkAAA38 From: Qing Luo When sctp_skb_recv_datagram() detects RCV_SHUTDOWN, it breaks out of the loop and returns NULL without setting *err. While current callers happen to work correctly (sctp_recvmsg pre-initializes err to 0, sctp_ulpevent_read_nxtinfo doesn't use err), this is inconsistent with the generic __skb_wait_for_more_packets() in net/core/datagram.c which explicitly sets *err =3D 0 on shutdown. Set *err =3D 0 explicitly for correctness and robustness against future callers. Signed-off-by: Qing Luo --- net/sctp/socket.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index c7b9e325ec1c..b8ec295e3a2f 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -9117,9 +9117,10 @@ struct sk_buff *sctp_skb_recv_datagram(struct sock *= sk, int flags, int *err) if (error) goto no_packet; =20 - if (sk->sk_shutdown & RCV_SHUTDOWN) + if (sk->sk_shutdown & RCV_SHUTDOWN) { + *err =3D 0; break; - + } =20 /* User doesn't want to wait. */ error =3D -EAGAIN; --=20 2.25.1 Thanks for the review. On reflection, I agree that the ERR_PTR refactoring should be dropped. Hone= stly, the refactored version ends up being more convoluted rather than simp= lifying things, so I=E2=80=99ll revert to the original &err interface to ke= ep it consistent with skb_recv_datagram(). Regarding the *err =3D 0 fix for the shutdown path =E2=80=94 my intention t= here was purely defensive, aligning with the pattern used in __skb_wait_for= _more_packets(). As the commit message notes, the current callers are not a= ctually affected by this, so no real bug is introduced. That said, if you f= eel this change is still unnecessary, I=E2=80=99m happy to drop it as well.