On Mon, 2021-08-09 at 22:08 +0200, Vlastimil Babka wrote: > On 8/9/2021 8:44 PM, Mike Galbraith wrote: > > > > > > slab_mutex -> flush_lock > > > > Bugger. That chain ending with cpu_hotplug_lock makes slub_cpu_dead() > > taking slab_mutex a non-starter for cpu hotplug as well. It's > > established early by kernel_init_freeable()..kmem_cache_destroy() as > > well as by slab_mem_going_offline_callback(). > > I suck at reading the lockdep splats, so I don't see yet how the "existing > reverse order" occurs - I do understand the order in the "lsbug". > What I also wonder is why didn't this occur also in the older RT trees with this > patch. Apparently (oops) nobody got around to hotplug+lockdep testing, RT or otherwise. I know I didn't, goldfish like attention span being used up by explosion testing ;-) -Mike
