On Thu 01-03-18 13:47:45, Daniel Vacek wrote:
In move_freepages() a BUG_ON() can be triggered on uninitialized page structures due to pageblock alignment. Aligning the skipped pfns in memmap_init_zone() the same way as in move_freepages_block() simply fixes those crashes.
This changelog doesn't describe how the fix works. Why doesn't memblock_next_valid_pfn return the first valid pfn as one would expect?
It would be also good put the panic info in the changelog.
Fixes: b92df1de5d28 ("[mm] page_alloc: skip over regions of invalid pfns where possible") Signed-off-by: Daniel Vacek neelx@redhat.com Cc: stable@vger.kernel.org
mm/page_alloc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cb416723538f..9edee36e6a74 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5359,9 +5359,14 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, /* * Skip to the pfn preceding the next valid one (or * end_pfn), such that we hit a valid pfn (or end_pfn)
* on our next iteration of the loop.
* on our next iteration of the loop. Note that it needs* to be pageblock aligned even when the region itself* is not as move_freepages_block() can shift ahead of* the valid region but still depends on correct page* metadata. */
pfn = memblock_next_valid_pfn(pfn, end_pfn) - 1;
pfn = (memblock_next_valid_pfn(pfn, end_pfn) &~(pageblock_nr_pages-1)) - 1;#endif continue; } -- 2.16.2