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authorqiuxishi <qiuxishi@gmail.com>2012-09-17 17:09:24 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-09-17 18:00:38 -0400
commitf14851af0ebb32745c6c5a2e400aa0549f9d20df (patch)
tree861f66b55bafe4a669d29469c24a3535ac1b8e2b /mm/memory_hotplug.c
parent0ba8f2d59304dfe69b59c034de723ad80f7ab9ac (diff)
memory hotplug: fix section info double registration bug
There may be a bug when registering section info. For example, on my Itanium platform, the pfn range of node0 includes the other nodes, so other nodes' section info will be double registered, and memmap's page count will equal to 3. node0: start_pfn=0x100, spanned_pfn=0x20fb00, present_pfn=0x7f8a3, => 0x000100-0x20fc00 node1: start_pfn=0x80000, spanned_pfn=0x80000, present_pfn=0x80000, => 0x080000-0x100000 node2: start_pfn=0x100000, spanned_pfn=0x80000, present_pfn=0x80000, => 0x100000-0x180000 node3: start_pfn=0x180000, spanned_pfn=0x80000, present_pfn=0x80000, => 0x180000-0x200000 free_all_bootmem_node() register_page_bootmem_info_node() register_page_bootmem_info_section() When hot remove memory, we can't free the memmap's page because page_count() is 2 after put_page_bootmem(). sparse_remove_one_section() free_section_usemap() free_map_bootmem() put_page_bootmem() [akpm@linux-foundation.org: add code comment] Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3ad25f9d1fc1..6a5b90d0cfd7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -126,9 +126,6 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
126 struct mem_section *ms; 126 struct mem_section *ms;
127 struct page *page, *memmap; 127 struct page *page, *memmap;
128 128
129 if (!pfn_valid(start_pfn))
130 return;
131
132 section_nr = pfn_to_section_nr(start_pfn); 129 section_nr = pfn_to_section_nr(start_pfn);
133 ms = __nr_to_section(section_nr); 130 ms = __nr_to_section(section_nr);
134 131
@@ -187,9 +184,16 @@ void register_page_bootmem_info_node(struct pglist_data *pgdat)
187 end_pfn = pfn + pgdat->node_spanned_pages; 184 end_pfn = pfn + pgdat->node_spanned_pages;
188 185
189 /* register_section info */ 186 /* register_section info */
190 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 187 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
191 register_page_bootmem_info_section(pfn); 188 /*
192 189 * Some platforms can assign the same pfn to multiple nodes - on
190 * node0 as well as nodeN. To avoid registering a pfn against
191 * multiple nodes we check that this pfn does not already
192 * reside in some other node.
193 */
194 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
195 register_page_bootmem_info_section(pfn);
196 }
193} 197}
194#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 198#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
195 199