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authorYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>2014-10-29 14:50:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-29 16:33:14 -0700
commit35dca71c1fad13616d9ea336c05730071793b63a (patch)
tree90e753169614b2f9bc91db8d01f1eb02e7ac6a01 /mm/memory_hotplug.c
parenteaf3a659086e1d1d85dc8fbce4007e3c9076e0b3 (diff)
downloadlwn-35dca71c1fad13616d9ea336c05730071793b63a.tar.gz
lwn-35dca71c1fad13616d9ea336c05730071793b63a.zip
memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
When hot adding the same memory after hot removal, the following messages are shown: WARNING: CPU: 20 PID: 6 at mm/page_alloc.c:4968 free_area_init_node+0x3fe/0x426() ... Call Trace: dump_stack+0x46/0x58 warn_slowpath_common+0x81/0xa0 warn_slowpath_null+0x1a/0x20 free_area_init_node+0x3fe/0x426 hotadd_new_pgdat+0x90/0x110 add_memory+0xd4/0x200 acpi_memory_device_add+0x1aa/0x289 acpi_bus_attach+0xfd/0x204 acpi_bus_attach+0x178/0x204 acpi_bus_scan+0x6a/0x90 acpi_device_hotplug+0xe8/0x418 acpi_hotplug_work_fn+0x1f/0x2b process_one_work+0x14e/0x3f0 worker_thread+0x11b/0x510 kthread+0xe1/0x100 ret_from_fork+0x7c/0xb0 The detaled explanation is as follows: When hot removing memory, pgdat is set to 0 in try_offline_node(). But if the pgdat is allocated by bootmem allocator, the clearing step is skipped. And when hot adding the same memory, the uninitialized pgdat is reused. But free_area_init_node() checks wether pgdat is set to zero. As a result, free_area_init_node() hits WARN_ON(). This patch clears pgdat which is allocated by bootmem allocator in try_offline_node(). Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Wang Nan <wangnan0@huawei.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Reviewed-by: Toshi Kani <toshi.kani@hp.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> 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.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 29d8693d0c61..252e1dbbed86 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1912,7 +1912,6 @@ void try_offline_node(int nid)
unsigned long start_pfn = pgdat->node_start_pfn;
unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
unsigned long pfn;
- struct page *pgdat_page = virt_to_page(pgdat);
int i;
for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
@@ -1941,10 +1940,6 @@ void try_offline_node(int nid)
node_set_offline(nid);
unregister_one_node(nid);
- if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
- /* node data is allocated from boot memory */
- return;
-
/* free waittable in each zone */
for (i = 0; i < MAX_NR_ZONES; i++) {
struct zone *zone = pgdat->node_zones + i;