From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34360 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669AbdIUOyx (ORCPT ); Thu, 21 Sep 2017 10:54:53 -0400 Subject: Patch "docs: disable KASLR when debugging kernel" has been added to the 4.13-stable tree To: zhouzhouyi@gmail.com, corbet@lwn.net, gregkh@linuxfoundation.org, jan.kiszka@siemens.com, kbingham@kernel.org, natale.patriciello@gmail.com Cc: , From: Date: Thu, 21 Sep 2017 16:55:03 +0200 Message-ID: <1506005703180238@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled docs: disable KASLR when debugging kernel to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: docs-disable-kaslr-when-debugging-kernel.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From e604f1cb85367d2e5fd4cf253296d190996da81a Mon Sep 17 00:00:00 2001 From: Zhouyi Zhou Date: Fri, 7 Jul 2017 16:51:45 +0800 Subject: docs: disable KASLR when debugging kernel From: Zhouyi Zhou commit e604f1cb85367d2e5fd4cf253296d190996da81a upstream. commit 6807c84652b0 ("x86: Enable KASLR by default") enables KASLR by default on x86. While KASLR will confuse gdb which resolve kernel symbol address from symbol table of vmlinux. We should turn off KASLR for kernel debugging. Signed-off-by: Zhouyi Zhou Reviewed-by: Kieran Bingham Acked-by: Jan Kiszka Signed-off-by: Jonathan Corbet Cc: Natale Patriciello Signed-off-by: Greg Kroah-Hartman --- Documentation/dev-tools/gdb-kernel-debugging.rst | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/Documentation/dev-tools/gdb-kernel-debugging.rst +++ b/Documentation/dev-tools/gdb-kernel-debugging.rst @@ -31,11 +31,13 @@ Setup CONFIG_DEBUG_INFO_REDUCED off. If your architecture supports CONFIG_FRAME_POINTER, keep it enabled. -- Install that kernel on the guest. +- Install that kernel on the guest, turn off KASLR if necessary by adding + "nokaslr" to the kernel command line. Alternatively, QEMU allows to boot the kernel directly using -kernel, -append, -initrd command line switches. This is generally only useful if you do not depend on modules. See QEMU documentation for more details on - this mode. + this mode. In this case, you should build the kernel with + CONFIG_RANDOMIZE_BASE disabled if the architecture supports KASLR. - Enable the gdb stub of QEMU/KVM, either Patches currently in stable-queue which might be from zhouzhouyi@gmail.com are queue-4.13/docs-disable-kaslr-when-debugging-kernel.patch