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mm/memory_hotplug: set magic number to page->freelist instead of page->lru.next 

[ Upstream commit ddffe98d16 ]

To identify that pages of page table are allocated from bootmem
allocator, magic number sets to page->lru.next.

But page->lru list is initialized in reserve_bootmem_region().  So when
calling free_pagetable(), the function cannot find the magic number of
pages.  And free_pagetable() frees the pages by free_reserved_page() not
put_page_bootmem().

But if the pages are allocated from bootmem allocator and used as page
table, the pages have private flag.  So before freeing the pages, we
should clear the private flag by put_page_bootmem().

Before applying the commit 7bfec6f47b ("mm, page_alloc: check multiple
page fields with a single branch"), we could find the following visible
issue:

  BUG: Bad page state in process kworker/u1024:1
  page:ffffea103cfd8040 count:0 mapcount:0 mappi
  flags: 0x6fffff80000800(private)
  page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
  bad because of flags: 0x800(private)
  <snip>
  Call Trace:
  [...] dump_stack+0x63/0x87
  [...] bad_page+0x114/0x130
  [...] free_pages_prepare+0x299/0x2d0
  [...] free_hot_cold_page+0x31/0x150
  [...] __free_pages+0x25/0x30
  [...] free_pagetable+0x6f/0xb4
  [...] remove_pagetable+0x379/0x7ff
  [...] vmemmap_free+0x10/0x20
  [...] sparse_remove_one_section+0x149/0x180
  [...] __remove_pages+0x2e9/0x4f0
  [...] arch_remove_memory+0x63/0xc0
  [...] remove_memory+0x8c/0xc0
  [...] acpi_memory_device_remove+0x79/0xa5
  [...] acpi_bus_trim+0x5a/0x8d
  [...] acpi_bus_trim+0x38/0x8d
  [...] acpi_device_hotplug+0x1b7/0x418
  [...] acpi_hotplug_work_fn+0x1e/0x29
  [...] process_one_work+0x152/0x400
  [...] worker_thread+0x125/0x4b0
  [...] kthread+0xd8/0xf0
  [...] ret_from_fork+0x22/0x40

And the issue still silently occurs.

Until freeing the pages of page table allocated from bootmem allocator,
the page->freelist is never used.  So the patch sets magic number to
page->freelist instead of page->lru.next.

[isimatu.yasuaki@jp.fujitsu.com: fix merge issue]
  Link: http://lkml.kernel.org/r/722b1cc4-93ac-dd8b-2be2-7a7e313b3b0b@gmail.com
Link: http://lkml.kernel.org/r/2c29bd9f-5b67-02d0-18a3-8828e78bbb6f@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yasuaki Ishimatsu 2017-02-22 15:45:13 -08:00 committed by Greg Kroah-Hartman
parent 6145171a6b
commit a5f043b241
3 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/mm/init_64.c
View File

@ -689,7 +689,7 @@ static void __meminit free_pagetable(struct page *page, int order)
if (PageReserved(page)) {
__ClearPageReserved(page);
magic = (unsigned long)page->lru.next;
magic = (unsigned long)page->freelist;
if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
while (nr_pages--)
put_page_bootmem(page++);

5
mm/memory_hotplug.c
View File

@ -179,7 +179,7 @@ static void release_memory_resource(struct resource *res)
void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
page->lru.next = (struct list_head *) type;
page->freelist = (void *)type;
SetPagePrivate(page);
set_page_private(page, info);
page_ref_inc(page);
@ -189,11 +189,12 @@ void put_page_bootmem(struct page *page)
{
unsigned long type;
type = (unsigned long) page->lru.next;
type = (unsigned long) page->freelist;
BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
if (page_ref_dec_return(page) == 1) {
page->freelist = NULL;
ClearPagePrivate(page);
set_page_private(page, 0);
INIT_LIST_HEAD(&page->lru);

2
mm/sparse.c
View File

@ -662,7 +662,7 @@ static void free_map_bootmem(struct page *memmap)
>> PAGE_SHIFT;
for (i = 0; i < nr_pages; i++, page++) {
magic = (unsigned long) page->lru.next;
magic = (unsigned long) page->freelist;
BUG_ON(magic == NODE_INFO);