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. I have found one bug in v7. We were not able to initialize NOP struct klp_func when the patches module is not loaded. It was because func->new_func was NULL. I have fixed it in separate patch for an easier review. Note that the original Jason's patch did not have this problem because func->new_func was always NULL there. But this required NOP-specific handling also on other locations, namely klp_ftrace_handler() and klp_check_stack_func(). 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 (5): livepatch: Use lists to manage patches, objects and functions livepatch: Initial support for dynamic structures livepatch: Allow to unpatch only functions of the given type livepatch: Support separate list for replaced patches. livepatch: Add atomic replace Petr Mladek (3): livepatch: Free only structures with initialized kobject livepatch: Correctly handle atomic replace for not yet loaded modules livepatch: Atomic replace and cumulative patches documentation Documentation/livepatch/cumulative-patches.txt | 83 ++++++ include/linux/livepatch.h | 59 +++- kernel/livepatch/core.c | 394 ++++++++++++++++++++++--- kernel/livepatch/core.h | 4 + kernel/livepatch/patch.c | 31 +- kernel/livepatch/patch.h | 4 +- kernel/livepatch/transition.c | 41 ++- 7 files changed, 566 insertions(+), 50 deletions(-) create mode 100644 Documentation/livepatch/cumulative-patches.txt -- 2.13.6 -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
