From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751507AbdH3Vjy (ORCPT ); Wed, 30 Aug 2017 17:39:54 -0400 Received: from mx0a-00190b01.pphosted.com ([67.231.149.131]:40982 "EHLO mx0a-00190b01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205AbdH3Vjx (ORCPT ); Wed, 30 Aug 2017 17:39:53 -0400 From: Jason Baron To: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Cc: jpoimboe@redhat.com, jeyu@kernel.org, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com Subject: [PATCH v2 0/3] livepatch: introduce atomic replace Date: Wed, 30 Aug 2017 17:38:42 -0400 Message-Id: X-Mailer: git-send-email 1.9.1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-08-30_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1708300329 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-08-30_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1708300329 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, In testing livepatch, I found that when doing cumulative patches, if a patched function is completed reverted by a subsequent patch (back to its original state) livepatch does not revert the funtion to its original state. Specifically, if patch A introduces a change to function 1, and patch B reverts the change to function 1 and introduces changes to say function 2 and 3 as well, the change that patch A introducd to function 1 is still present. This could be addressed by first completely removing patch A (disable and then rmmod) and then inserting patch B (insmod and enable), but this leaves an unpatched window. In discussing this issue with Josh on the kpatch mailing list, he mentioned that we could get 'atomic replace working properly', and that is the direction of this patchset: https://www.redhat.com/archives/kpatch/2017-June/msg00005.html Patches: 1) livepatch: Add klp_object and klp_func dynamic iterators A prep patch for the 'atomic replace' feature such that dynamic objects and functions can be allocated. 2) livepatch: add atomic replace Core feature. 3) livepatch: Add a sysctl livepatch_mode for atomic replace Introduces a knob for enabling atomic replace. This patch is really only meant for testing purposes, and should not be considered for application. The intention is for the livepatch module generator to set the 'replace' field in the klp_patch structure such that the kernel knows to do the atomic replace. Thanks, -Jason v1-v2: -removed the func_iter and obj_iter (Petr Mladek) -initialiing kobject structure for no_op functions using: klp_init_object() and klp_init_func() -added a 'replace' field to klp_patch, similar to the immediate field -a 'replace' patch now disables all previous patches -tried to shorten klp_init_patch_no_ops()... -Simplified logic klp_complete_transition (Petr Mladek) Jason Baron (3): livepatch: Add dynamic klp_object and klp_func iterators livepatch: add atomic replace livepatch: Add a sysctl livepatch_mode for atomic replace include/linux/livepatch.h | 108 ++++++++++++++++++++++++- kernel/livepatch/core.c | 182 +++++++++++++++++++++++++++++++++++++++--- kernel/livepatch/core.h | 5 ++ kernel/livepatch/patch.c | 19 +++-- kernel/livepatch/patch.h | 4 +- kernel/livepatch/transition.c | 47 ++++++++++- kernel/sysctl.c | 12 +++ 7 files changed, 352 insertions(+), 25 deletions(-) -- 2.6.1