On 17/05/2019 15:36, Jan Beulich wrote: >>>> On 17.05.19 at 15:24, <[email protected]> wrote: >> On 17/05/2019 15:17, Jan Beulich wrote: >>>>>> On 08.05.19 at 13:31, <[email protected]> wrote: >>>> Commit 753ba43d6d16e688 ("xen/sched: fix credit2 smt idle handling") >>>> introduced a regression when switching cpus between cpupools. >>>> >>>> When assigning a cpu to a cpupool with credit2 being the default >>>> scheduler csched2_deinit_pdata() is called for the credit2 private data >>>> after the new scheduler's private data has been hooked to the per-cpu >>>> scheduler data. Unfortunately csched2_deinit_pdata() will cycle through >>>> all per-cpu scheduler areas it knows of for removing the cpu from the >>>> respective sibling masks including the area of the just moved cpu. This >>>> will (depending on the new scheduler) either clobber the data of the >>>> new scheduler or in case of sched_rt lead to a crash. >>>> >>>> Avoid that by removing the cpu from the list of active cpus in credit2 >>>> data first. >>>> >>>> The opposite problem is occurring when removing a cpu from a cpupool: >>>> init_pdata() of credit2 will access the per-cpu data of the old >>>> scheduler. >>>> >>>> Signed-off-by: Juergen Gross <[email protected]> >>> >>> May I ask what the disposition of this is? I've noticed too late >>> that I've backported the commit being fixed here without >>> waiting for this fix to go in. I'd prefer the stable trees, in >>> particular 4.11 for the impending 4.11.2 release, to be able >>> to pick this up soon. >> >> Dario already gave his Reviewed-by: > > Oh, my fault then - apologies.
NP. In case you need the pointer: https://lists.xen.org/archives/html/xen-devel/2019-05/msg00734.html Juergen _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
