From 122e093c1734361dedb64f65c99b93e28e4624f4 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Mon, 28 Jun 2021 19:33:26 -0700 Subject: mm/page_alloc: fix memory map initialization for descending nodes On systems with memory nodes sorted in descending order, for instance Dell Precision WorkStation T5500, the struct pages for higher PFNs and respectively lower nodes, could be overwritten by the initialization of struct pages corresponding to the holes in the memory sections. For example for the below memory layout [ 0.245624] Early memory node ranges [ 0.248496] node 1: [mem 0x0000000000001000-0x0000000000090fff] [ 0.251376] node 1: [mem 0x0000000000100000-0x00000000dbdf8fff] [ 0.254256] node 1: [mem 0x0000000100000000-0x0000001423ffffff] [ 0.257144] node 0: [mem 0x0000001424000000-0x0000002023ffffff] the range 0x1424000000 - 0x1428000000 in the beginning of node 0 starts in the middle of a section and will be considered as a hole during the initialization of the last section in node 1. The wrong initialization of the memory map causes panic on boot when CONFIG_DEBUG_VM is enabled. Reorder loop order of the memory map initialization so that the outer loop will always iterate over populated memory regions in the ascending order and the inner loop will select the zone corresponding to the PFN range. This way initialization of the struct pages for the memory holes will be always done for the ranges that are actually not populated. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/YNXlMqBbL+tBG7yq@kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=213073 Link: https://lkml.kernel.org/r/20210624062305.10940-1-rppt@kernel.org Fixes: 0740a50b9baa ("mm/page_alloc.c: refactor initialization of struct page for holes in memory layout") Signed-off-by: Mike Rapoport Cc: Boris Petkov Cc: Robert Shteynfeld Cc: Baoquan He Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 8ae31622deef..9afb8998e7e5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2474,7 +2474,6 @@ extern void set_dma_reserve(unsigned long new_dma_reserve); extern void memmap_init_range(unsigned long, int, unsigned long, unsigned long, unsigned long, enum meminit_context, struct vmem_altmap *, int migratetype); -extern void memmap_init_zone(struct zone *zone); extern void setup_per_zone_wmarks(void); extern int __meminit init_per_zone_wmark_min(void); extern void mem_init(void); -- cgit v1.2.3