From nobody Fri Feb 13 03:05:51 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9362F111AD for ; Mon, 3 Jun 2024 08:30:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717403443; cv=none; b=GI+qWnsP23gk+Gzkt1TGQG+h5hASaJPf/t8llYw6H4J3ex+deciMWV+ABFKVGBF2GVrhbOTMUS5CFV/x1dEhEmX28hmXSRgxDZ2EbQaCRmxxDLWYwvkm/TsuiYnD3qX1lfcEOPIA0JDLOHSf4Hdl4lQlC4SdL+uddd63xUYnvNw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717403443; c=relaxed/simple; bh=qHk9ZMgx+Y3r7cbyMy8jKoU1ZUxSVBLcogFQF5N90CY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=seB70MRZBlGFdHCXrbUqugb1+KzLRppn6BRNTQLbpc1TNAPbbOxPQJAJzdkSNFU2Y3tleqXo2kMOwNx3T6bSrD1hcG/KzpuoqwkZF3sBV7sN5K61/UoPaWudCgUM3MX7KElcQ8yQmgEvFPgxk3nLtKui+KtHE/AhDqSVWAwNngo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lHC57QyX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lHC57QyX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3FA4C2BD10; Mon, 3 Jun 2024 08:30:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717403443; bh=qHk9ZMgx+Y3r7cbyMy8jKoU1ZUxSVBLcogFQF5N90CY=; h=From:To:Cc:Subject:Date:From; b=lHC57QyX3D4WTOmuJnlpeDoHNuFbdt1UA2S3MUOJ+hfsyx1k2dS5SVF/ex+YlAClq yhKvW9rwwkEpwPcn2ppfeg82cr7Rq8hKvhmgFjLc9prmL6h/ZtM3iPjaQBvdQ8Zc0W dO3o9rRXXXbaizB3NCz9qUGXBcIXM0ElA2ITeBp3G+y+IqtyCGn01wRoLFWlV7B2Lb z+GIvuH8h5dCWOMsTrDqwx+T3LxOH0d6pLPtzdevAy93TOKmZp89h4/+9YT3MobsQq CvgvoIsV2RFnRuRyqKzC3p2vej9y5qm4az9pG/uvSLJ6D9iqg6xbkcstfuxZR12An3 Cqtv2W1Ug9WmA== From: Borislav Petkov To: X86 ML Cc: Tom Lendacky , LKML , David Kaplan , Borislav Petkov Subject: [PATCH] x86/kexec: Fix bug with call depth tracking Date: Mon, 3 Jun 2024 10:30:36 +0200 Message-ID: <20240603083036.637-1-bp@kernel.org> X-Mailer: git-send-email 2.43.0 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 Content-Type: text/plain; charset="utf-8" From: David Kaplan The call to cc_platform_has() triggers a fault and system crash if call dep= th tracking is active because the GS segment has been reset by load_segments()= and GS_BASE is now 0 but call depth tracking uses per-CPU variables to operate. Call cc_platform_has() earlier in the function when GS is still valid. [ bp: Massage. ] Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky --- arch/x86/kernel/machine_kexec_64.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_k= exec_64.c index b180d8e497c3..90b1946c06e5 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -295,8 +295,15 @@ void machine_kexec_cleanup(struct kimage *image) void machine_kexec(struct kimage *image) { unsigned long page_list[PAGES_NR]; - void *control_page; + unsigned int host_mem_enc_active; int save_ftrace_enabled; + void *control_page; + + /* + * This must be done before load_segments() since if call depth tracking + * is used then GS must be valid to make any function calls. + */ + host_mem_enc_active =3D cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT); =20 #ifdef CONFIG_KEXEC_JUMP if (image->preserve_context) @@ -358,7 +365,7 @@ void machine_kexec(struct kimage *image) (unsigned long)page_list, image->start, image->preserve_context, - cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)); + host_mem_enc_active); =20 #ifdef CONFIG_KEXEC_JUMP if (image->preserve_context) --=20 2.43.0