Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965269AbeALT43 (ORCPT + 1 other); Fri, 12 Jan 2018 14:56:29 -0500 Received: from mx0b-00190b01.pphosted.com ([67.231.157.127]:52850 "EHLO mx0b-00190b01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965133AbeALT41 (ORCPT ); Fri, 12 Jan 2018 14:56:27 -0500 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 v5 0/3] livepatch: introduce atomic replace Date: Fri, 12 Jan 2018 14:55:13 -0500 Message-Id: X-Mailer: git-send-email 1.9.1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-12_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=603 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1801120267 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-12_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=633 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1801120267 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi, While using 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 introduced 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 Thanks, -Jason v4-v5 -re-base onto remove-immediate branch (removing immediate dependencies) -replaced modules can be re-enabled by doing rmmod and then insmod v3-v4: -add static patch, objects, funcs to linked lists to simplify iterator -break-out pure function movement as patch 2/3 v2-v3: -refactor how the dynamic nops are calculated (Petr Mladek) -move the creation of dynamic nops to enable/disable paths -add klp_replaced_patches list to indicate patches that can be re-enabled -dropped 'replaced' field -renamed dynamic fields in klp_func, object and patch -moved iterator implementation to kernel/livepatch/core.c -'inherit' nop immediate flag -update kobject_put free'ing logic (Petr Mladek) 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: use lists to manage patches, objects and functions livepatch: shuffle core.c function order livepatch: add atomic replace include/linux/livepatch.h | 25 +- kernel/livepatch/core.c | 626 ++++++++++++++++++++++++++++++------------ kernel/livepatch/core.h | 6 + kernel/livepatch/patch.c | 22 +- kernel/livepatch/patch.h | 4 +- kernel/livepatch/transition.c | 49 +++- 6 files changed, 537 insertions(+), 195 deletions(-) -- 2.6.1