On Thu 02-11-17 10:00:59, Pavel Tatashin wrote: > > > On 11/02/2017 09:54 AM, Michal Hocko wrote: > > On Thu 02-11-17 09:39:58, Pavel Tatashin wrote: > > [...] > > > Hi Michal, > > > > > > Previously as before my project? That is because memory for all struct > > > pages > > > was always zeroed in memblock, and in __free_one_page() page_is_buddy() > > > was > > > always returning false, thus we never tried to incorrectly remove it from > > > the list: > > > > > > 837 list_del(&buddy->lru); > > > > > > Now, that memory is not zeroed, page_is_buddy() can return true after > > > kexec > > > when memory is dirty (unfortunately memset(1) with CONFIG_VM_DEBUG does > > > not > > > catch this case). And proceed further to incorrectly remove buddy from the > > > list. > > > > OK, I thought this was a regression from one of the recent patches. So > > the problem is not new. Why don't we see the same problem during the > > standard boot? > > Because, I believe, BIOS is zeroing all the memory for us.
I thought you were runnning with the debugging which poisons all the allocated memory... > > > This is why we must initialize the computed buddy page beforehand. > > > > Ble, this is really ugly. I will think about it more. > > > > Another approach that I considered is to split loop inside > deferred_init_range() into two loops: one where we initialize pages by > calling __init_single_page(), another where we free them to buddy allocator > by calling deferred_free_range(). Yes, that would make much more sense to me. -- Michal Hocko SUSE Labs
