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    Subject[PATCH] x86/mm, hibernate: Fix misjudgment of register setup_data page to nosave region
    Date
    The reserve setup_data action break usable regions to not align to
    page size. As following case:

    BIOS-e820: [mem 0x0000000000088000-0x00000000000bffff] reserved
    BIOS-e820: [mem 0x0000000000100000-0x0000000094caffff] usable
    ...
    e820: update [mem 0x93c5f018-0x93c6f057] usable ==> usable /* reserve setup_data */
    e820: update [mem 0x93c4f018-0x93c5e057] usable ==> usable /* reserve setup_data */
    ...
    reserve setup_data: [mem0x0000000000088000-0x00000000000bffff] reserved
    reserve setup_data: [mem0x0000000000100000-0x0000000093c4f017] usable /* not align */
    reserve setup_data: [mem0x0000000093c4f018-0x0000000093c5e057] usable /* not align */
    reserve setup_data: [mem0x0000000093c5e058-0x0000000093c5f017] usable /* not align */
    reserve setup_data: [mem0x0000000093c5f018-0x0000000093c6f057] usable /* not align */
    reserve setup_data: [mem0x0000000093c6f058-0x0000000094caffff] usable

    The codes in e820_mark_nosave_regions() check pfn of each e820
    entry to find out the hole between two entries then register it to
    nosave region. This logic misjudges the non-align but continuous usable
    region, then register one page in usable region to nosave. As following:

    PM: Registered nosave memory: [mem 0x000c0000-0x000fffff]
    PM: Registered nosave memory: [mem 0x93c4f000-0x93c4ffff] /* misjudgment */
    PM: Registered nosave memory: [mem 0x93c5e000-0x93c5efff] /* misjudgment */
    PM: Registered nosave memory: [mem 0x93c5f000-0x93c5ffff] /* misjudgment */
    PM: Registered nosave memory: [mem 0x93c6f000-0x93c6ffff] /* misjudgment */
    PM: Registered nosave memory: [mem 0x94cb0000-0x960affff]

    The issue causes some usable pages didn't collect to hibernate snapshot image.
    And, it also misjudges a usable page in nosave regions then hibernate resuming
    process interrupted by the unsafe pages checking:
    https://bugzilla.opensuse.org/show_bug.cgi?id=913885

    This patch changed the code in e820_mark_nosave_regions() to check the
    address instead of pfn to avoid above issue.

    Cc: Pavel Machek <pavel@ucw.cz>
    Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    Cc: Len Brown <len.brown@intel.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Cc: Takashi Iwai <tiwai@suse.de>
    Cc: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
    ---
    arch/x86/kernel/e820.c | 7 ++++---
    1 file changed, 4 insertions(+), 3 deletions(-)

    diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
    index 49f8864..6eae021 100644
    --- a/arch/x86/kernel/e820.c
    +++ b/arch/x86/kernel/e820.c
    @@ -687,15 +687,16 @@ void __init parse_e820_ext(u64 phys_addr, u32 data_len)
    void __init e820_mark_nosave_regions(unsigned long limit_pfn)
    {
    int i;
    - unsigned long pfn = 0;
    + unsigned long pfn = 0, pfnaddr = 0;

    for (i = 0; i < e820.nr_map; i++) {
    struct e820entry *ei = &e820.map[i];

    - if (pfn < PFN_UP(ei->addr))
    + if (pfnaddr < ei->addr)
    register_nosave_region(pfn, PFN_UP(ei->addr));

    - pfn = PFN_DOWN(ei->addr + ei->size);
    + pfnaddr = ei->addr + ei->size;
    + pfn = PFN_DOWN(pfnaddr);
    if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
    register_nosave_region(PFN_UP(ei->addr), pfn);

    --
    1.8.4.5


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