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=1794273174; b=g/sS1790ob9mvfZr582ZY//rTmXPgSuJvGVoiREENYNLFH0d9Z34Tq78iLSvFGKAGEs3 8i6GYZNv7giB9l65OMN1BvYgGYX5E+CP0H7OoYbkOmcBEj4ajGtbduc0y3Au1caAz4G+a ZnHZHegcSJvX0gj0UZhYEfeeAX8Ei++0PflyDW0vmW67DuoRzXgWXhU5FGDIaabTlEgAA 1zpvhW+AXdQjf5TpRG6iSn0Tf0u98G1XWqBdkcZZBesi+pHAC2bBUotAKQsduWz43U7pZ botzDzhPOaHwPYk6q4ONSQNOp/6CZvgbhKa4Gc24Nh43dr9PZrstKRxZgiyTvkNEJTg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273174; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=LtQn44I1ixcdEAqhI0VoOGVxJ9aa6x8G6LUvttZUei0=; b=umN/wTED+0kuKxCsLY8WcJOysdiCfYrCHV4jiykE+gNpAzYa5mBgUKfMtlGJaFYeu31m hvn8g8SxYffFy5Jg9tdMZsjCQD2PvxeOcFIsYAX6uB18gUI+MgPiJj+O8STrDl/LeacW6 33NMdi+vsR+CT7bBAfSGyolmSLBFUqPTCPOSG0pLTbJZmn+h4ZZYq6sW6cy57FrZ92g3S QRJslfSXciKk7cRHm9/cI6Y9iQhKYEhryCyAtHzFrKlRC/535amTr5Gd6uEeyRdmjPtrl DfUX3qG0/iHLxwmiFW8TKH01LaHfOBf5LKlH11o9S5p4aExKAFqp/T7SJUdiAmGqtzA== 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=X3QAsJbl; 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 49580606A31C for ; Tue, 10 Nov 2026 01:12:54 +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=X3QAsJbl Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AE341F0089F; Tue, 10 Nov 2026 01:12:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273174; bh=LtQn44I1ixcdEAqhI0VoOGVxJ9aa6x8G6LUvttZUei0=; h=From:To:Cc:Subject:Date; b=X3QAsJbl1EruXY1pZnpYVOAP17gahNabB7IwK/D22fMNQR1iVeVIhmsaHd5LIh3gS OfQJbEBTyER94etvZiz8lALmtNJGncofgmSu3xBt2vnhHxGytbOn3U2kg+/T4vLezw pdNOBZWctEworYV9FP45kJLm6tSGqazXszP5TIoPy1sCc2KEXnvvtPFkAvA3JZ4i3P QKPUvVxJuXhF6neKhArCy38/pBGPrbRk2E+DiehYAs+LO/dErCqN0a2eYdvEw5/6uA 9VV0L6pXpfH4nagvcELl0qU+5ZOvBPkSOE3LwQO/aI260YW/cuAlceiXigtcq44+ZC o5eD+HnainGFQ== From: Sasha Levin To: shubham@octane.security, michael.christie@oracle.com, mst@redhat.com Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] vhost-scsi: zero misaligned I/O bounce pages" failed to apply to 6.6-stable tree Date: Mon, 9 Nov 2026 20:12:52 -0500 Message-ID: <20261109201252-failed-6.6-01c3a5fa6d64@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 01c3a5fa6d641c93c7cef4fb25c5f12938316e18 # git commit -s git send-email --to '' --in-reply-to '20261109201252-failed-6.6-01c3a5fa6d64@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 01c3a5fa6d641c93c7cef4fb25c5f12938316e18 Mon Sep 17 00:00:00 2001 From: Shubham Antil Date: Tue, 20 Oct 2026 16:25:03 +0530 Subject: [PATCH] vhost-scsi: zero misaligned I/O bounce pages The misaligned I/O fallback copies the full bounce scatterlist to the request buffer during completion. If a data-in command transfers less than requested, part of a newly allocated bounce page can remain unwritten. Allocate bounce pages with __GFP_ZERO so all bytes copied during completion have a defined value. This path is already the slow fallback for misaligned I/O, so the added initialization cost is acceptable. Found during an LLM-assisted source audit and validated with a QEMU/KVM vhost-scsi target using misaligned data-in commands. Fixes: 5ced58bfa132 ("vhost-scsi: Fix alignment handling with windows") Cc: stable@vger.kernel.org Assisted-by: LLM (OpenAI Codex, gpt-5.6-sol) Signed-off-by: Shubham Antil Reviewed-by: Mike Christie Signed-off-by: Michael S. Tsirkin Message-ID: <20261020105503.75904-1-shubham@octane.security> --- drivers/vhost/scsi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 1a0b75cc4cefe..8b166bf5ae773 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -944,7 +944,12 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter, } for_each_sgtable_sg(sg_table, sg, i) { - page = alloc_page(GFP_KERNEL); + /* + * Completion copies the full bounce buffer, including bytes the + * target did not write. This is already the slow fallback for + * misaligned I/O, so zeroing is acceptable here. + */ + page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) { ret = -ENOMEM; goto err; -- 2.53.0