From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 657493B8BDA; Mon, 17 Aug 2026 13:55:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974962; cv=none; b=McuVyKdTnUNzq9CwO5a33OspE/GaFxJAt9OMFwXn4z4HftOTVhvWb90F8reZvSjKG/tkitV/cowWzdG5KW+tIHBui9psIatvbEesKT8O5PvI40JbfIkDfAIS3QFftv6jVF/PY9hAmfnmQCMz/PtWfZlM2xFNNIxueAbQ3Ke1o+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974962; c=relaxed/simple; bh=SAK7L5tPtXgn+y9ccx1YBsW4lrlGBbSG9bjdx6laeqo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fyMubidNkttmlwvACA7EkjlKcodIRr3ZhgKSlYl9KgY6h0xz7xBe4fSRiFyXv+MUwI7ryTanZzbyad4Y6vls/wD2+zqm3h2a+ig7KEy9n9KYlv1H+raAiVElyRZgPtkEDbW8BC7dBjAIAiYFTym2XfXkWQUISX4FP/8tayye49E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=k7mdctVJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="k7mdctVJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA49F1F00A3D; Mon, 17 Aug 2026 13:55:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786974958; bh=DEco5GD/l46AmEQV4FjnG+og7WOm7CzwNm/trdXtzAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=k7mdctVJDu+nxCSAEX9xiWecrkGXU/OZ86IbaSd6+rSSUsvGheNoBr/f3AkmJpgmV s9qWjR+qsCDHrr+r6iMVzrleRk2kyqTZmbIiSHr+9tbl1KANNvhSpWgZFcjTIt72jV oaORsQSidKUFtL6wJEyDuyfCOfxW9eRhN1erF5fw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jia Jia , Stefan Hajnoczi , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 6.18 074/250] vhost-scsi: reject feature changes after endpoint Date: Mon, 17 Aug 2026 15:30:35 +0200 Message-ID: <20260817132539.467595082@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132536.466235697@linuxfoundation.org> References: <20260817132536.466235697@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jia Jia [ Upstream commit 42bc45df5905e2b7dccb72adaf7730f66cfbe03f ] vhost_scsi_setup_vq_cmds() runs from VHOST_SCSI_SET_ENDPOINT and allocates each command's protection scatterlist array (prot_sgl) according to the acknowledged VIRTIO_SCSI_F_T10_PI bit. The command pools are not rebuilt when VHOST_SET_FEATURES changes that bit later. Although virtio feature bits must not change after feature negotiation, vhost_scsi_set_features() currently accepts such a request after the endpoint is active and updates acked_features. Enabling T10-PI after endpoint setup therefore leaves prot_sgl NULL while the I/O path follows the new feature bit. For a 129-page protection payload, vhost_scsi_mapal() passes the missing first chunk to sg_alloc_table_chained(): sg_alloc_table_chained(table, 129, first_chunk=NULL, nents_first_chunk=inline_sg_cnt) sg_pool_index() then hits: BUG_ON(nents > SG_CHUNK_SIZE); /* 129 > 128 */ The kernel reported the following call trace and register state: Call Trace: ? __sg_alloc_table+0x1d8/0x250 ? __pfx_vhost_run_work_list+0x10/0x10 [vhost] sg_alloc_table_chained+0x59/0xf0 ? __pfx_sg_pool_alloc+0x10/0x10 ? vhost_scsi_calc_sgls.constprop.0+0x43/0x60 [vhost_scsi] vhost_scsi_handle_vq+0xf02/0x1700 [vhost_scsi] ? __pfx_vhost_scsi_handle_vq+0x10/0x10 [vhost_scsi] vhost_scsi_handle_kick+0x37/0x50 [vhost_scsi] vhost_run_work_list+0x8e/0xd0 [vhost] vhost_task_fn+0xe1/0x210 ret_from_fork+0x348/0x540 RIP: 0010:0x4 CR2 = 0x4 RSP: 0018:ffffc90000dbf940 EFLAGS: 00010202 RAX: ffffffff82396810 RBX: ffff88811dc28b80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000820 RDI: 0000000000000081 VHOST_F_LOG_ALL is a vhost-specific runtime feature and remains the only exception. Reject changes to any feature other than VHOST_F_LOG_ALL while the endpoint is active. This preserves the existing runtime log toggle while preventing feature-dependent command resources and data-path state from becoming inconsistent. Userspace must clear the endpoint before changing any other negotiated feature and set the endpoint up again afterward. Fixes: bf2d650391be ("vhost-scsi: Allocate T10 PI structs only when enabled") Signed-off-by: Jia Jia Reviewed-by: Stefan Hajnoczi Signed-off-by: Michael S. Tsirkin Message-ID: <20260726144314.1652934-1-physicalmtea@gmail.com> Signed-off-by: Sasha Levin --- drivers/vhost/scsi.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 65a57de0080ef..29716ce714554 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -2231,6 +2231,7 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) { struct vhost_virtqueue *vq; bool is_log, was_log; + u64 old_features; int i; if (features & ~VHOST_SCSI_FEATURES) @@ -2246,6 +2247,14 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) if (!vs->dev.nvqs) goto out; + old_features = vs->vqs[0].vq.acked_features; + if (vs->vs_tpg && + ((features ^ old_features) & + ~(1ULL << VHOST_F_LOG_ALL))) { + mutex_unlock(&vs->dev.mutex); + return -EBUSY; + } + is_log = features & (1 << VHOST_F_LOG_ALL); /* * All VQs should have same feature. -- 2.53.0