From nobody Mon Oct 6 08:31:24 2025 Received: from mx0b-00190b01.pphosted.com (mx0b-00190b01.pphosted.com [67.231.157.127]) (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 525C12E8E1C; Wed, 23 Jul 2025 13:47:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.157.127 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753278462; cv=none; b=mBEbVeKpSghKElkKISeNrLahnQkcI+g4BMjEwtbbJyQGLb8h10P4ipuhTnNFGpvypBtLFwQLR4yuT+c17me4gsh0Ftx+PFgkir50Yiv4VvY7lVBhZCOGOvhQ3TY0RVscm6kSThIvHMWMrREGGV4szTzGbNJy4/bE8fZdmoMFOyg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753278462; c=relaxed/simple; bh=w559i7lP3utZp0dD42OMBd+22gRjpxtrRK+Ak52fhnY=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=J5XQaZmWaSVZX0gKsdkGBQxnbO9o+eyymJ6P1CAqWQWuRrL1whXocpmX8gBMrBjiCiA+0YoiduouDgb8/DupxDHQDKsYaembzFGjOyy97DMBiqzZMng6+rauljpimVCwi4SleG0uc0oJqaPDPPMWPGpfyesMiNlWn5lodqT/bZA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=akamai.com; spf=pass smtp.mailfrom=akamai.com; dkim=pass (2048-bit key) header.d=akamai.com header.i=@akamai.com header.b=n+LSOkZg; arc=none smtp.client-ip=67.231.157.127 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=akamai.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=akamai.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=akamai.com header.i=@akamai.com header.b="n+LSOkZg" Received: from pps.filterd (m0122330.ppops.net [127.0.0.1]) by mx0b-00190b01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 56ND8xgP008138; Wed, 23 Jul 2025 14:46:28 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=akamai.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=jan2016.eng; bh=I4cU5grOnj5Eszz3Ro/qg7rQXFNKBPCaFOjNapYWe+Q=; b=n+LSOkZgXJG3 zTnvYjdKrwxf+7fsndKMlNRFY6jS6g3Gy8J5VRKUXybhmtEXRnXzKkZKfCr6/+nj i8K4Cv7w4FlgAdir1tLCZHnBCKF/VkPPhTK6wpl2532gjArjp/HB6wk41ekWeRHf Q0AGom+8QW7BZh8cC6kU8N0x0gkWeUNWwSSCr/iM28UpdIONX593f7NEYy+up//l HdPcTL2ZXLNztl1xS6pvrJctXghgSsORlae0QdQnvO0Fawkw8r2rtr2i4fGKjCqf M+EklRZsJEuOlgwTqwsW2QAkMtsJZSKY7SRo8s+s7RDvJogg4AAtbgkBi/Elbm3S 1fn4R4PaMw== Received: from prod-mail-ppoint3 (a72-247-45-31.deploy.static.akamaitechnologies.com [72.247.45.31] (may be forged)) by mx0b-00190b01.pphosted.com (PPS) with ESMTPS id 482w3v31uk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 23 Jul 2025 14:46:28 +0100 (BST) Received: from pps.filterd (prod-mail-ppoint3.akamai.com [127.0.0.1]) by prod-mail-ppoint3.akamai.com (8.18.1.2/8.18.1.2) with ESMTP id 56NCp7xq010652; Wed, 23 Jul 2025 09:46:01 -0400 Received: from email.msg.corp.akamai.com ([172.27.91.22]) by prod-mail-ppoint3.akamai.com (PPS) with ESMTPS id 480r8y1art-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 23 Jul 2025 09:46:01 -0400 Received: from usma1ex-exedge1.msg.corp.akamai.com (172.27.91.34) by usma1ex-dag4mb3.msg.corp.akamai.com (172.27.91.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1748.26; Wed, 23 Jul 2025 09:46:00 -0400 Received: from usma1ex-dag4mb8.msg.corp.akamai.com (172.27.91.27) by usma1ex-exedge1.msg.corp.akamai.com (172.27.91.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1748.26; Wed, 23 Jul 2025 09:46:00 -0400 Received: from bos-lhvzmp.bos01.corp.akamai.com (172.28.221.177) by usma1ex-dag4mb8.msg.corp.akamai.com (172.27.91.27) with Microsoft SMTP Server id 15.2.1748.26 via Frontend Transport; Wed, 23 Jul 2025 09:46:00 -0400 Received: by bos-lhvzmp.bos01.corp.akamai.com (Postfix, from userid 42339) id 5D9F815F582; Wed, 23 Jul 2025 09:46:00 -0400 (EDT) From: Michael Zhivich To: , CC: , , , , , Michael Zhivich Subject: [PATCH v3 6.1] x86/bugs: Fix use of possibly uninit value in amd_check_tsa_microcode() Date: Wed, 23 Jul 2025 09:45:59 -0400 Message-ID: <20250723134559.2371838-1-mzhivich@akamai.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <2025072219-mulberry-shallow-da0d@gregkh> References: <2025072219-mulberry-shallow-da0d@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-07-23_02,2025-07-22_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 phishscore=0 suspectscore=0 mlxscore=0 bulkscore=0 malwarescore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2507230116 X-Proofpoint-ORIG-GUID: DstfN6dF6kf8NuCzCA9UQffWcOYX1gtZ X-Authority-Analysis: v=2.4 cv=bcRrUPPB c=1 sm=1 tr=0 ts=6880e7b4 cx=c_pps a=x6EWYSa6xQJ7sIVSrxzgOQ==:117 a=x6EWYSa6xQJ7sIVSrxzgOQ==:17 a=Wb1JkmetP80A:10 a=VwQbUJbxAAAA:8 a=X7Ea-ya5AAAA:8 a=QyML1Wa_BHPz27VLx9cA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzIzMDExOCBTYWx0ZWRfX+z8YB25sRlgz D7n6BHcqiNVzufALrTc2rrhSjWa1sXdbF6Af9r832qfe7DMTkrQOTsvs53Z6fYiiWSu8NyQwsVQ yXldZOMVia676uO6L4Pu6JEavSfp+2tgHbhEF9jEDmnzxmy6052Le/ST/TFjm8l9fyMATDIvGW7 nddKL6v/UJ8DUy81c4dh9Zk15hxL7Pn4JtnxQqu0WyIPzothB6G8uqq3ko4DsWSabWjtJff1pid T095yXySrgWzQuXbu1IZwKwGgKxk9wvtMAgYNLxE+IqdGcDwPyROLH36TD1uSFf70cP6/3Ya/LX 2PvYoS8zLJCxTOHl1lOL+ijzAmdqqU77I9Yqfn8rEkQoQE9nVK2N2gxXRXyJHz5zia4yeLg6aOq ecf1qH10XVdkimMyrPU9hZVIoNCZbylgg+paCR0iXx8+8fsDxD8opZfw+XZjgnpz792LXmBW X-Proofpoint-GUID: DstfN6dF6kf8NuCzCA9UQffWcOYX1gtZ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-07-23_02,2025-07-23_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 spamscore=0 mlxscore=0 suspectscore=0 impostorscore=0 adultscore=0 bulkscore=0 priorityscore=1501 clxscore=1015 malwarescore=0 mlxlogscore=928 lowpriorityscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2507230118 Content-Type: text/plain; charset="utf-8" For kernels compiled with CONFIG_INIT_STACK_NONE=3Dy, the value of __reserv= ed field in zen_patch_rev union on the stack may be garbage. If so, it will prevent correct microcode check when consulting p.ucode_rev, resulting in incorrect mitigation selection. This is a stable-only fix. Cc: Signed-off-by: Michael Zhivich Fixes: d12145e8454f ("x86/bugs: Add a Transient Scheduler Attacks mitigatio= n") --- Changes in v3: - separate "fixes" tag for each stable arch/x86/kernel/cpu/amd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 4785d41558d6..2d71c329b347 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -563,6 +563,8 @@ static bool amd_check_tsa_microcode(void) p.model =3D c->x86_model; p.ext_model =3D c->x86_model >> 4; p.stepping =3D c->x86_stepping; + /* reserved bits are expected to be 0 in test below */ + p.__reserved =3D 0; =20 if (c->x86 =3D=3D 0x19) { switch (p.ucode_rev >> 8) { --=20 2.34.1