x86, ioapic: Fix potential resume deadlock

BugLink: http://bugs.launchpad.net/bugs/793702

commit b64ce24daffb634b5b3133a2e411bd4de50654e8 upstream.

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>
Link: http://lkml.kernel.org/r/20110518233157.385970138@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index ca9e2a3..e437778 100644 (file)
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -615,14 +615,14 @@ 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;
        }