Messages in this thread | | | Date | Thu, 2 Nov 2017 14:54:23 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH v1 1/1] mm: buddy page accessed before initialized |
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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?
> This is why we must initialize the computed buddy page beforehand.
Ble, this is really ugly. I will think about it more. -- Michal Hocko SUSE Labs
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