AuxXxilium/linux_dsm_epyc7002
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Yasuaki Ishimatsu ddffe98d16 mm/memory_hotplug: set magic number to page->freelist instead of page->lru.next 
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>
2017-02-22 16:41:29 -08:00
..
boot Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 14:04:37 -08:00
configs
crypto
entry
events perf/x86/intel: Add Kaby Lake support 2017-02-11 21:28:23 +01:00
hyperv drivers: hv: Turn off write permission on the hypercall page 2017-02-10 15:48:00 +01:00
ia32
include char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
kernel char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
kvm Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 12:52:55 -08:00
lguest
lib
math-emu
mm mm/memory_hotplug: set magic number to page->freelist instead of page->lru.next 2017-02-22 16:41:29 -08:00
net bpf: fix unlocking of jited image when module ronx not set 2017-02-21 13:30:14 -05:00
oprofile
pci
platform char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
power
purgatory
ras
realmode
tools
um
video
xen xen: features and fixes for 4.11-rc0 2017-02-21 13:53:41 -08:00
.gitignore
Kbuild
Kconfig arm64 updates for 4.11: 2017-02-22 10:46:44 -08:00
Kconfig.cpu
Kconfig.debug This renames the (now inaccurate) CONFIG_DEBUG_RODATA and related config 2017-02-21 17:56:45 -08:00
Makefile
Makefile_32.cpu
Makefile.um