On Wed, 2019-05-08 at 13:31 +0200, Juergen Gross 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. > These issues will drive us all crazy, at some point! :-(
I really wish I managed to put a cpupool test in OSSTest. I guess I can pickup my old draft, but I need some time to put together an OSSTest dev environment again. :-/ Anyway... > Signed-off-by: Juergen Gross <jgr...@suse.com> > Reviewed-by: Dario Faggioli <dfaggi...@suse.com> Thanks and Regards -- Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <<This happens because _I_ choose it to happen!>> (Raistlin Majere)
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