On Mon, 9 Feb 2015, Josh Poimboeuf wrote: > 2) As mentioned above, kthreads which are always sleeping on a patched function > will never transition to the new universe. This is really a minor issue > (less than 1% of patches). It's not necessarily something that needs to be > resolved with this patch set, but it would be good to have some discussion > about it regardless. > > To overcome this issue, I have 1/2 an idea: we could add some stack checking > code to the ftrace handler itself to transition the kthread to the new > universe after it re-enters the function it was originally sleeping on, if > the stack doesn't already have have any other to-be-patched functions. > Combined with the klp_transition_work_fn()'s periodic stack checking of > sleeping tasks, that would handle most of the cases (except when trying to > patch the high-level thread_fn itself). > > But then how do you make the kthread wake up? As far as I can tell, > wake_up_process() doesn't seem to work on a kthread (unless I messed up my > testing somehow). What does kGraft do in this case? wake_up_process() really should work for (p->flags & PF_KTHREAD) task_struct. What was your testing scenario? -- Jiri Kosina SUSE Labs -- 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
