From mboxrd@z Thu Jan 1 00:00:00 1970 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 0E041143757; Wed, 19 Jun 2024 13:22:57 +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=1718803377; cv=none; b=mCD/3ajEaddwAITu8qC8dTEuyMc68ue6rjtnsGfvaiLZcspW5pUZ4klcCtdSG12gOpD46LjEV8lfK5bZgZY9djke3gcdV/5rQYcXwPW3JMmUcroDVZM2v14mHGnPhUctVBWv0rPt1e1GvJq8TqCjlRINOTQ/IcRAoG64AxEIbNg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718803377; c=relaxed/simple; bh=QsWca1lSsPAqKhorSbdkEvpUSYobetYvik4gO0iAEW0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t4L8b+RIjdLTpn7BAxUHHC1WnNLqzGCre4swR5W3ZCpW2Smr4L5rQHVM+yjIKZo8AEg8dErPY8agQ+IT+eoiMLurlBfA9/3AbKlcCm39VcRRaAt9qXYDD2KgmsU6oz9nIDSW7jUnasX0LA9lzhL7yHOj7kpf44ZKYUhoB+dpSF0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=U4qCbf8G; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="U4qCbf8G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 876DEC2BBFC; Wed, 19 Jun 2024 13:22:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718803376; bh=QsWca1lSsPAqKhorSbdkEvpUSYobetYvik4gO0iAEW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U4qCbf8GOKQ2i5GIwMrEjzs0xa+c7shmYALgZQmXI4DumKhjAY+j5JFmVha5rVko8 xKqqUmNc04uMhNuOG3EBOOV1/cbmWrO+zZ5NAPyd7M7Vt1BLUqFUMHNkJdf1OL9ILW jQAEoh2AkGpgSAzLs02cQYtxU0kZ6FK3dcRAhDZo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Kaplan , "Borislav Petkov (AMD)" , Tom Lendacky , stable@kernel.org Subject: [PATCH 6.9 215/281] x86/kexec: Fix bug with call depth tracking Date: Wed, 19 Jun 2024 14:56:14 +0200 Message-ID: <20240619125618.234415637@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240619125609.836313103@linuxfoundation.org> References: <20240619125609.836313103@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Kaplan commit 93c1800b3799f17375989b0daf76497dd3e80922 upstream. The call to cc_platform_has() triggers a fault and system crash if call depth 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. ] Fixes: 5d8213864ade ("x86/retbleed: Add SKL return thunk") Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky Cc: Link: https://lore.kernel.org/r/20240603083036.637-1-bp@kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/machine_kexec_64.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- 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 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 = cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT); #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); #ifdef CONFIG_KEXEC_JUMP if (image->preserve_context)