From 7568fb63f57ac8672f8bf2018171255441238882 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Tue, 25 Aug 2015 22:12:37 -0700 Subject: [PATCH] mm: Check if section present during memory block (un)registering Tony found on his setup, if memory block size 512M will cause crash during booting. BUG: unable to handle kernel paging request at ffffea0074000020 IP: [] get_nid_for_pfn+0x17/0x40 PGD 128ffcb067 PUD 128ffc9067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.2.0-rc8 #1 ... Call Trace: [] ? register_mem_sect_under_node+0x66/0xe0 [] register_one_node+0x17b/0x240 [] ? pci_iommu_alloc+0x6e/0x6e [] topology_init+0x3c/0x95 [] do_one_initcall+0xcd/0x1f0 The system has non continuous RAM address: BIOS-e820: [mem 0x0000001300000000-0x0000001cffffffff] usable BIOS-e820: [mem 0x0000001d70000000-0x0000001ec7ffefff] usable BIOS-e820: [mem 0x0000001f00000000-0x0000002bffffffff] usable BIOS-e820: [mem 0x0000002c18000000-0x0000002d6fffefff] usable BIOS-e820: [mem 0x0000002e00000000-0x00000039ffffffff] usable So there are start sections in memory block not present. For example: memory block : [0x2c18000000, 0x2c20000000) 512M first three sections are not present. Current register_mem_sect_under_node() assume first section is present, but memory block section number range [start_section_nr, end_section_nr] would include not present section. For arch that support vmemmap, we don't setup memmap for struct page area within not present sections area. So skip the pfn range that belong to absent section. Also fixes unregister_mem_sect_under_nodes() that assume one section per memory block. Reported-by: Tony Luck Tested-by: Tony Luck Fixes: bdee237c0343 ("x86: mm: Use 2GB memory block size on large memory x86-64 systems") Fixes: 982792c782ef ("x86, mm: probe memory block size for generic x86 64bit") Signed-off-by: Yinghai Lu Cc: stable@vger.kernel.org #v3.15 Signed-off-by: Greg Kroah-Hartman --- drivers/base/node.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/base/node.c b/drivers/base/node.c index 560751bad294..ae98ebaf6313 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -390,7 +390,18 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid) sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); sect_end_pfn += PAGES_PER_SECTION - 1; for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { - int page_nid; + int page_nid, scn_nr; + + /* + * memory block could have several absent sections from start. + * skip pfn range from absent section + */ + scn_nr = pfn_to_section_nr(pfn); + if (!present_section_nr(scn_nr)) { + pfn = round_down(pfn + PAGES_PER_SECTION, + PAGES_PER_SECTION) - 1; + continue; + } /* * memory block could have several absent sections from start. @@ -436,10 +447,22 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk, return -ENOMEM; nodes_clear(*unlinked_nodes); - sect_start_pfn = section_nr_to_pfn(phys_index); - sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; + sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); + sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); + sect_end_pfn += PAGES_PER_SECTION - 1; for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { - int nid; + int nid, scn_nr; + + /* + * memory block could have several absent sections from start. + * skip pfn range from absent section + */ + scn_nr = pfn_to_section_nr(pfn); + if (!present_section_nr(scn_nr)) { + pfn = round_down(pfn + PAGES_PER_SECTION, + PAGES_PER_SECTION) - 1; + continue; + } nid = get_nid_for_pfn(pfn); if (nid < 0) -- 2.30.2