From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794458693; b=rRxFq+yapxGqbEQTJKk/S7prYxaI2I0MHuQtf8Z0iJnPVpbESDsSZ318G3WcLZi5G8gk 4yvNAZzKJPgH787JP4Q/pZUoOe7mAPlKabdehO6PN4CFzhY58ZkrTiWL+4b0YW1dtx4NY rGBt3mWveHc5KX7zESuAU7aiVAfOQJ+nyTL7fjNKz/OhMfZFtUUwIU5lJXf67um/aS+2B 1bwUZBTvzI95vCyBwH7ub41v8wWsubaZig3IoAFMN5ffOqcNc8emzW1DmZvFOJTcgl2zv BapizBjORlUjtYu6Gg+dvuWhdd9Eo6L7t33pzhBF1L4qiFmhQM23P9UAzRAXEDu4Thg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794458693; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=qda8UjmOzXvU9jQqMPgjGDyPtN4WI5O+pSBtOUbHh0M=; b=C5LiXW5eAq+aWb/cwGvPWXD+L4UmFLzEftcybS+xaek0MN5Wd3BAzfqMYFgKQZb3bu6H Ll59wK5XaONGZZQ1KfvkUn7olnZu9dtH8sw+y5Jsi619V1NOzJw5IafNjvqxY+zlrZl/C 00GnYU2HiIwHGAiNV7kD28JGRy+k6xAmo69wji+SDiCyAc7JOe9w45mH88aG0Z4E3tJpR gNeVp0O/WaCnm5qGiw2OoLZkjCuARG7LgdhHoQXE5Mza8pNLAQd9Uk90hlrwcvrRPjHLL Y1bTUyal+BKqqpDKsDdoWWT5JjNNPffbcwEnUsjCA9bLeJKqETNQghNlR4FviFr3Myg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=F3bpFutJ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C96B606A321 for ; Thu, 12 Nov 2026 04:44:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=F3bpFutJ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F42F1F00A06; Thu, 12 Nov 2026 04:44:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794458693; bh=qda8UjmOzXvU9jQqMPgjGDyPtN4WI5O+pSBtOUbHh0M=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=F3bpFutJEvOw7enhgM1oWLRdfIU8+hgCJbIolelYZWNDobhEVjPEBwqGX2JggwxIh L8/GpCmvhXJyWNYfZXTxSYekl1GkoAXiB9rxjBynK5h1aY9GWMLZZjX5VgT0qZm/rc tLKxBcLVZhJmrfglH+/aks69GFyKxgLkCFd1YsPemdf28++S20CUuB6nmGSrR18KF+ LDpIx5PmdB1ge1XLaqejPVVO52+UFqTS2AZmuZafB+gjhI60g7JxEpUHVjrS7Sz5da CD4Zle57T5UhH87JtEBQymyKpkwf/eHLY01O0EUxQv1Nrk5mlnpDA6QAB/OW711+aR jUmNu30yAWLvg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC net v3 7/7] net/iucv: return EOF to a reader parked when the peer closes Reply-To: sashiko-reviews@lists.linux.dev To: "Bryam Vargas" Cc: linux-s390@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261110-b4-disp-2a6b4364-v3-7-35677b68e697@proton.me> References: <20261110-b4-disp-2a6b4364-v3-0-35677b68e697@proton.me> <20261110-b4-disp-2a6b4364-v3-7-35677b68e697@proton.me> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 12 Nov 2026 04:44:51 +0000 X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > From: Bryam Vargas >=20 > A recvmsg() that starts after the peer closed returns 0. One that was > already waiting returns -ENOTCONN: its wait ends on sk_state and does > not ask whether anything is left to read. In a z/VM guest over > HiperSockets that was every parked reader, 13627 of 13627 on net-next > [1]. poll() does not report EPOLLRDHUP for the close either. >=20 > Return EOF from the wait too when the socket is IUCV_DISCONN with > nothing left to read. As for a call that starts afterwards, it does not > matter how the socket got there: the peer's FIN, a severed z/VM path, a > transmit error, a window update that could not be sent or the device > going down. EOF does not say that all the peer sent was read: a severed > z/VM path drops the messages not yet received, for either call. Set > RCV_SHUTDOWN where the HiperSockets FIN is applied, as TCP does: poll() > then reports EPOLLRDHUP and EPOLLRDNORM for the close, and EPOLLHUP if > the socket had shut down its own sending. The other ways still report > none of the three. >=20 > Fixes: 561e036006dc ("[AF_IUCV]: Implementation of a skb backlog queue") > Fixes: 3881ac441f64 ("af_iucv: add HiperSockets transport") > Reported-by: Hidayath Khan > Closes: https://lore.kernel.org/netdev/82691101-92d7-4838-b16e-2e41a83f65= d0@linux.ibm.com/ > Link: https://lore.kernel.org/netdev/51a4a40a-f34b-4d41-b049-69aa53f4dcf5= @linux.ibm.com/ [1] > Cc: stable@vger.kernel.org # 6.18.x > Signed-off-by: Bryam Vargas Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110-b4-disp-2a= 6b4364-v3-0-35677b68e697@proton.me?part=3D7