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=1794272908; b=OGsKIa4Qo4AxVQn1kSe/Z7A30RrcIkv219YmV+LhmOiHNy+uUmQRoK0W3u/9dvSoseqj vhRTJeEUWDqXYN0xASNnEFGIhebVptz5GjMVb4VW3pzr1j1z7UsqrwOkYV+FVhsz22kMx tem/xERTF9aqP31PR5N8bYG6hYJHPMv1ip7gOBok0MRE+EI+YM4V4Dox1Vf95fMwA3YXu uRjYJB9P4RnS77/l0OZhYtK4oAe30VZ28DxTFOYqJonBXEUSpr+2Pk40RXenpxUzwZNuF U1Cc36+ZoFn0bIZTGbliETX5BfnNY2SbQJltpZolKGl+3WHqJ6AzGVxQVIgikvCCiVw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794272908; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=Q32DzIPBgv2l/ezYrkMSTegKK5t8SWygjMoIi0tn3i0=; b=bffERl/+546jIwfxRF4lM2t95hffD0uuaQxLPjl4DmS3+F07dnU1fHt+MmSPNRA4Onmm geDPux7R9OP8xZwfmKUS2m6yWHESja0GGTiD+F6z3a1N2ozl3GOGQoxh673At4mX4EmgF 95Xr74I+GXfjxPhySyug+JUijGLiJGlWjr3PkWJfXxJ5u25i5O0OnwajmSoBs8RtS/D66 r+5F5nfbM6HBpvZU7WuHkjqzWMOG6m4Nhnm40Zslz8o/UjlEC/Wet7ISIsXZWmX3jCtUu /0nk2P9lPCUa74stOF1V1viGqTfcfyoApmEovb21YrLTd97CyDDUiOkbcS2aUNajp+A== 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=YeuVOCnw; 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 24F50606A31C for ; Tue, 10 Nov 2026 01:08:28 +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=YeuVOCnw Received: by smtp.kernel.org (Postfix) with ESMTPSA id 728481F0089F; Tue, 10 Nov 2026 01:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794272908; bh=Q32DzIPBgv2l/ezYrkMSTegKK5t8SWygjMoIi0tn3i0=; h=From:To:Cc:Subject:Date; b=YeuVOCnwLZoEHiASqdsnuvt7YxoybFGHhTDXfGyzXh94XgtFFxYjxZ1880pZfW0Xm v+bRUX3duc75y1AuWp1ecKroQCdrHHas0MntiFZfB6pdGU/qvc3QiIx4/5RQy3VBvT D08856bguH2AwLBKDdiSr8MmxkEG07J6OFoGykBJNDVMq+nhmtpm8qqZUsgTUyRhzo o8vQdzLp6wYvmu3CbnY6HMUBcubDzbg03Rg5UTd6+62HSf1pY4gxVUyrFUHNzYLSeG 51iqigyMEp0Tla23Wt8mi3JMaVuefn7kqMvVEXEr5tHzy8M9mHVkyGRIM7OIN2p3uw AVM133nBJYW/Q== 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 6.12-stable tree Date: Mon, 9 Nov 2026 20:08:26 -0500 Message-ID: <20261109200826-failed-6.12-01c3a5fa6d64@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 6.12-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-6.12.y git checkout FETCH_HEAD git cherry-pick -x 01c3a5fa6d641c93c7cef4fb25c5f12938316e18 # git commit -s git send-email --to '' --in-reply-to '20261109200826-failed-6.12-01c3a5fa6d64@kernel.org' --subject-prefix 'PATCH 6.12.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