Messages in this thread | | | Date | Fri, 19 Jan 2018 16:58:58 +0100 | From | Petr Mladek <> | Subject | Re: [PATCH v5 0/3] livepatch: introduce atomic replace |
| |
On Fri 2018-01-12 14:55:13, Jason Baron wrote: > 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
JFYI, I have spent a lot of time reviewing the patchset this week. IMHO, it is basically correct. I am just not happy with the design, namely code symmetry, code duplication, and the way how "dynamic" and "nop" terms are used.
I have started to play with the code. Otherwise, it was pretty hard to be sure if another design would work. I think that I have something useful. But it still need some testing and clean up. I believe that I would be able to send it next week.
Best Regards, Petr
PS: Jason, you did a great job. Do not worry. I will keep you as the author of the patches even when I send an updated version.
| |