On Sun, 10 Nov 2019, Yu Zhao wrote: > On Sat, Nov 09, 2019 at 11:16:28PM +0000, Christopher Lameter wrote: > > On Sat, 9 Nov 2019, Yu Zhao wrote: > > > > > > struct page *page, *h; > > > > + unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL); > > > > + > > > > + if (!map) > > > > + return; > > > > > > What would happen if we are trying to allocate from the slab that is > > > being shut down? And shouldn't the allocation be conditional (i.e., > > > only when CONFIG_SLUB_DEBUG=y)? > > > > Kmalloc slabs are never shut down. > > Maybe I'm not thinking straight -- isn't it what caused the deadlock in > the first place? Well if kmalloc allocations become a problem then we have numerous issues all over the kernel to fix. > Kmalloc slabs can be shut down when memcg is on. Kmalloc needs to work even during shutdown of a memcg. Maybe we need to fix memcg to not allocate from the current memcg during shutdown?
