From 8783b6e2b2cb726f2734cf208d101f73ac1ba616 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 2 Aug 2012 10:37:03 -0700 Subject: [PATCH] mm: remove node_start_pfn checking in new WARN_ON for now Borislav Petkov reports that the new warning added in commit 88fdf75d1bb5 ("mm: warn if pg_data_t isn't initialized with zero") triggers for him, and it is the node_start_pfn field that has already been initialized once. The call trace looks like this: x86_64_start_kernel -> x86_64_start_reservations -> start_kernel -> setup_arch -> paging_init -> zone_sizes_init -> free_area_init_nodes -> free_area_init_node and (with the warning replaced by debug output), Borislav sees On node 0 totalpages: 4193848 DMA zone: 64 pages used for memmap DMA zone: 6 pages reserved DMA zone: 3890 pages, LIFO batch:0 DMA32 zone: 16320 pages used for memmap DMA32 zone: 798464 pages, LIFO batch:31 Normal zone: 52736 pages used for memmap Normal zone: 3322368 pages, LIFO batch:31 free_area_init_node: pgdat->node_start_pfn: 4423680 <---- On node 1 totalpages: 4194304 Normal zone: 65536 pages used for memmap Normal zone: 4128768 pages, LIFO batch:31 free_area_init_node: pgdat->node_start_pfn: 8617984 <---- On node 2 totalpages: 4194304 Normal zone: 65536 pages used for memmap Normal zone: 4128768 pages, LIFO batch:31 free_area_init_node: pgdat->node_start_pfn: 12812288 <---- On node 3 totalpages: 4194304 Normal zone: 65536 pages used for memmap Normal zone: 4128768 pages, LIFO batch:31 so remove the bogus warning for now to avoid annoying people. Minchan Kim is looking at it. Reported-by: Borislav Petkov Cc: Minchan Kim Cc: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 889532b..009ac28 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4511,7 +4511,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, pg_data_t *pgdat = NODE_DATA(nid); /* pg_data_t should be reset to zero when it's allocated */ - WARN_ON(pgdat->nr_zones || pgdat->node_start_pfn || pgdat->classzone_idx); + WARN_ON(pgdat->nr_zones || pgdat->classzone_idx); pgdat->node_id = nid; pgdat->node_start_pfn = node_start_pfn; -- 2.7.4