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    Subject[tip:x86/apic] x86, ioapic: Fix potential resume deadlock
    Commit-ID:  b64ce24daffb634b5b3133a2e411bd4de50654e8
    Gitweb: http://git.kernel.org/tip/b64ce24daffb634b5b3133a2e411bd4de50654e8
    Author: Daniel J Blueman <daniel.blueman@gmail.com>
    AuthorDate: Wed, 18 May 2011 16:31:31 -0700
    Committer: Ingo Molnar <mingo@elte.hu>
    CommitDate: Fri, 20 May 2011 13:40:41 +0200

    x86, ioapic: Fix potential resume deadlock

    Fix a potential deadlock when resuming; here the calling
    function has disabled interrupts, so we cannot sleep.

    Change the memory allocation flag from GFP_KERNEL to GFP_ATOMIC.

    TODO: We can do away with this memory allocation during resume
    by reusing the ioapic suspend/resume code that uses boot time
    allocated buffers, but we want to keep this -stable patch
    simple.

    Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
    Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
    Cc: <stable@kernel.org> # v2.6.38/39
    Link: http://lkml.kernel.org/r/20110518233157.385970138@sbsiddha-MOBL3.sc.intel.com
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    ---
    arch/x86/kernel/apic/io_apic.c | 4 ++--
    1 files changed, 2 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
    index 45fd33d..df63620 100644
    --- a/arch/x86/kernel/apic/io_apic.c
    +++ b/arch/x86/kernel/apic/io_apic.c
    @@ -621,14 +621,14 @@ struct IO_APIC_route_entry **alloc_ioapic_entries(void)
    struct IO_APIC_route_entry **ioapic_entries;

    ioapic_entries = kzalloc(sizeof(*ioapic_entries) * nr_ioapics,
    - GFP_KERNEL);
    + GFP_ATOMIC);
    if (!ioapic_entries)
    return 0;

    for (apic = 0; apic < nr_ioapics; apic++) {
    ioapic_entries[apic] =
    kzalloc(sizeof(struct IO_APIC_route_entry) *
    - nr_ioapic_registers[apic], GFP_KERNEL);
    + nr_ioapic_registers[apic], GFP_ATOMIC);
    if (!ioapic_entries[apic])
    goto nomem;
    }

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