Messages in this thread | | | Subject | Re: [PATCH] mm: deferred_init_memmap improvements | From | Anshuman Khandual <> | Date | Fri, 6 Oct 2017 12:18:31 +0530 |
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On 10/04/2017 08:59 PM, Pavel Tatashin wrote: > This patch fixes another existing issue on systems that have holes in > zones i.e CONFIG_HOLES_IN_ZONE is defined. > > In for_each_mem_pfn_range() we have code like this: > > if (!pfn_valid_within(pfn) > goto free_range; > > Note: 'page' is not set to NULL and is not incremented but 'pfn' advances.
page is initialized to NULL at the beginning of the function. PFN advances but we dont proceed unless pfn_valid_within(pfn) holds true which basically should have checked with arch call back if the PFN is valid in presence of memory holes as well. Is not this correct ?
> Thus means if deferred struct pages are enabled on systems with these kind > of holes, linux would get memory corruptions. I have fixed this issue by > defining a new macro that performs all the necessary operations when we > free the current set of pages.
If we bail out in case PFN is not valid, then how corruption can happen ?
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