On Sat, Jul 03, 2021 at 05:25:02AM +0000, Dennis Zhou wrote: > On Fri, Jul 02, 2021 at 10:14:44PM -0700, Guenter Roeck wrote: > > On Sat, Jul 03, 2021 at 04:04:49AM +0000, Dennis Zhou wrote: > > > Prior to "percpu: implement partial chunk depopulation", > > > pcpu_depopulate_chunk() was called only on the destruction path. This > > > meant the virtual address range was on its way back to vmalloc which > > > will handle flushing the tlbs for us. > > > > > > However, now that we call pcpu_depopulate_chunk() during the active > > > lifecycle of a chunk, we need to flush the tlb as well otherwise we can > > > end up accessing the wrong page through an invalid tlb mapping. > > > > > > This was reported in [1]. > > > > > > [1] https://lore.kernel.org/lkml/20210702191140.GA3166599@xxxxxxxxxxxx/ > > > > > > Fixes: f183324133ea ("percpu: implement partial chunk depopulation") > > > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > > Signed-off-by: Dennis Zhou <dennis@xxxxxxxxxx> > > > > Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > > > Thanks! > > Guenter > > > > I updated the tag and have applied this to for-5.14-fixes so it can get > some for-next exposure before I send a fix to Linus. > > Thanks for setting up the super easy repro! It made debugging this > significantly easier. > I'm pulling this because I think I'll need to do some aggregation to make this less expensive. I'll send some variant soon hopefully. Thanks, Dennis
