• Yasuaki Ishimatsu's avatar
    mm/memory_hotplug: set magic number to page->freelist instead of page->lru.next · ddffe98d
    Yasuaki Ishimatsu authored
    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
    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 7bfec6f4 ("mm, page_alloc: check multiple
    page fields with a single branch"), we could find the following visible
      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)
      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.comSigned-off-by: default avatarYasuaki 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
sparse.c 20.8 KB