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[209.132.180.67]) by mx.google.com with ESMTP id s11si1539391pgi.324.2018.11.29.01.45.52; Thu, 29 Nov 2018 01:46:07 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727761AbeK2Utn (ORCPT + 99 others); Thu, 29 Nov 2018 15:49:43 -0500 Received: from mx2.suse.de ([195.135.220.15]:47956 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725934AbeK2Utn (ORCPT ); Thu, 29 Nov 2018 15:49:43 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 35D22AD64; Thu, 29 Nov 2018 09:44:55 +0000 (UTC) From: Petr Mladek To: Jiri Kosina , Josh Poimboeuf , Miroslav Benes Cc: Jason Baron , Joe Lawrence , Evgenii Shatokhin , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Petr Mladek Subject: [PATCH v14 00/11] livepatch: Atomic replace feature Date: Thu, 29 Nov 2018 10:44:20 +0100 Message-Id: <20181129094431.7801-1-pmladek@suse.com> X-Mailer: git-send-email 2.13.7 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I have an updated present for your mailboxes. The atomic replace allows to create cumulative patches. They are useful when you maintain many livepatches and want to remove one that is lower on the stack. In addition it is very useful when more patches touch the same function and there are dependencies between them. All the changes were simple in principle but they required quite some refactoring again :-( IMHO, the biggest change is renaming klp_init_lists() ->klp_init_patch_before_free(). It does all init actions that need to succeed before klp_free() functions can be safely called. The main motivation was the need to initialize also the new .kobj_alive flags. Changes against v13: + Rename old_addr -> old_func instead of new_func -> new_addr. [Josh] + Do not add the helper macros to define structures. [Miroslav, Josh] + Add custom kobj_alive flag to reliably handle kobj state. [Miroslav] + Avoid renaming .forced flag to .module_put by calling klp_free functions only with taken module reference. [Josh] + Use list_add_tail() instead of list_add() when updating the dynamic lists of klp_object and klp_func structures. Note that this required also updating the order of messages from the pre/post callbacks in the selftest. [Josh, Miroslav] + Do not unnecessarily initialize ret variable in klp_add_nops(). [Miroslav] + Got rid of klp_discard_replaced_stuff(). [Josh] + Updated commit messages, comments and documentation, especially the section "Livepatch life-cycle" [Josh, Miroslav] Changes against v12: + Finish freeing the patch using workqueues to prevent deadlock against kobject code. + Check for valid pointers when initializing the dynamic lists objects and functions. + Mark klp_free_objects_dynamic() static. + Improved documentation and fixed typos Changes against v11: + Functional changes: + Livepatches get automatically unregistered when disabled. Note that the sysfs interface disappears at this point. It simplifies the API and code. The only drawback is that the patch can be enabled again only by reloading the module. + Refuse to load conflicting patches. The same function can be patched again only by a new cumulative patch that replaces all older ones. + Non-conflicting patches can be loaded and disabled in any order. + API related changes: + Change void *new_func -> unsigned long new_addr in struct klp_func. + Several new macros to hide implementation details and avoid casting when defining struct klp-func and klp_object. + Remove obsolete klp_register_patch() klp_unregister_patch() API + Change in selftest against v4: + Use new macros to define struct klp_func and klp_object. + Remove klp_register_patch()/klp_unregister_patch() calls. + Replace load_mod() + wait_for_transition() with three variants load_mod(), load_lp(), load_lp_nowait(). IMHO, it is easier to use because we need to detect the end of transaction another way after disable_lp() now. + Replaced unload_mod() with two variants unload_mod(), unload_lp() to match the above change. + Wait for the end of transition in disable_lp() instead of the unreliable check of the sysfs interface. Note that I did not touch the logs with expected result. They stay exactly the same as in v4 posted by Joe. I hope that it is a good sign ;-) Changes against v10: + Bug fixes and functional changes: + Handle Nops in klp_ftrace_handled() to avoid infinite loop [Mirek] + Really add dynamically allocated klp_object into the list [Petr] + Clear patch->replace when transition finishes [Josh] + Refactoring and clean up [Josh]: + Replace enum types with bools + Avoid using ERR_PTR + Remove too paranoid warnings + Distinguish registered patches by a flag instead of a list + Squash some functions + Update comments, documentation, and commit messages + Squashed and split patches to do more controversial changes later Changes against v9: + Fixed check of valid NOPs for already loaded objects, regression introduced in v9 [Joe, Mirek] + Allow to replace even disabled patches [Evgenii] Changes against v8: + Fixed handling of statically defined struct klp_object with empty array of functions [Joe, Mirek] + Removed redundant func->new_func assignment for NOPs [Mirek] + Improved some wording [Mirek] Changes against v7: + Fixed handling of NOPs for not-yet-loaded modules + Made klp_replaced_patches list static [Mirek] + Made klp_free_object() public later [Mirek] + Fixed several reported typos [Mirek, Joe] + Updated documentation according to the feedback [Joe] + Added some Acks [Mirek] Changes against v6: + used list_move when disabling replaced patches [Jason] + renamed KLP_FUNC_ORIGINAL -> KLP_FUNC_STATIC [Mirek] + used klp_is_func_type() in klp_unpatch_object() [Mirek] + moved static definition of klp_get_or_add_object() [Mirek] + updated comment about synchronization in forced mode [Mirek] + added user documentation + fixed several typos Jason Baron (2): livepatch: Use lists to manage patches, objects and functions livepatch: Add atomic replace Joe Lawrence (1): selftests/livepatch: introduce tests Petr Mladek (8): livepatch: Change unsigned long old_addr -> void *old_func in struct klp_func livepatch: Shuffle klp_enable_patch()/klp_disable_patch() code livepatch: Consolidate klp_free functions livepatch: Refuse to unload only livepatches available during a forced transition livepatch: Simplify API by removing registration step livepatch: Remove Nop structures when unused livepatch: Atomic replace and cumulative patches documentation livepatch: Remove ordering and refuse loading conflicting patches Documentation/livepatch/callbacks.txt | 489 +----------- Documentation/livepatch/cumulative-patches.txt | 102 +++ Documentation/livepatch/livepatch.txt | 170 ++--- MAINTAINERS | 1 + include/linux/livepatch.h | 48 +- kernel/livepatch/core.c | 849 ++++++++++++++------- kernel/livepatch/core.h | 5 + kernel/livepatch/patch.c | 57 +- kernel/livepatch/patch.h | 3 +- kernel/livepatch/transition.c | 35 +- lib/Kconfig.debug | 21 + lib/Makefile | 2 + lib/livepatch/Makefile | 15 + lib/livepatch/test_klp_atomic_replace.c | 57 ++ lib/livepatch/test_klp_callbacks_busy.c | 43 ++ lib/livepatch/test_klp_callbacks_demo.c | 121 +++ lib/livepatch/test_klp_callbacks_demo2.c | 93 +++ lib/livepatch/test_klp_callbacks_mod.c | 24 + lib/livepatch/test_klp_livepatch.c | 51 ++ lib/livepatch/test_klp_shadow_vars.c | 236 ++++++ samples/livepatch/livepatch-callbacks-demo.c | 13 +- samples/livepatch/livepatch-sample.c | 13 +- samples/livepatch/livepatch-shadow-fix1.c | 14 +- samples/livepatch/livepatch-shadow-fix2.c | 14 +- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/livepatch/Makefile | 8 + tools/testing/selftests/livepatch/README | 43 ++ tools/testing/selftests/livepatch/config | 1 + tools/testing/selftests/livepatch/functions.sh | 203 +++++ .../testing/selftests/livepatch/test-callbacks.sh | 587 ++++++++++++++ .../testing/selftests/livepatch/test-livepatch.sh | 168 ++++ .../selftests/livepatch/test-shadow-vars.sh | 60 ++ 32 files changed, 2608 insertions(+), 939 deletions(-) create mode 100644 Documentation/livepatch/cumulative-patches.txt create mode 100644 lib/livepatch/Makefile create mode 100644 lib/livepatch/test_klp_atomic_replace.c create mode 100644 lib/livepatch/test_klp_callbacks_busy.c create mode 100644 lib/livepatch/test_klp_callbacks_demo.c create mode 100644 lib/livepatch/test_klp_callbacks_demo2.c create mode 100644 lib/livepatch/test_klp_callbacks_mod.c create mode 100644 lib/livepatch/test_klp_livepatch.c create mode 100644 lib/livepatch/test_klp_shadow_vars.c create mode 100644 tools/testing/selftests/livepatch/Makefile create mode 100644 tools/testing/selftests/livepatch/README create mode 100644 tools/testing/selftests/livepatch/config create mode 100644 tools/testing/selftests/livepatch/functions.sh create mode 100755 tools/testing/selftests/livepatch/test-callbacks.sh create mode 100755 tools/testing/selftests/livepatch/test-livepatch.sh create mode 100755 tools/testing/selftests/livepatch/test-shadow-vars.sh -- 2.13.7