[Xen-devel] [PATCH 2 of 7] KEXEC BUG: nmi_shootdown_cpus doesn't look after the interrupt flag

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

nmi_shootdown_cpus is part of the kexec path, coming from a panic, and
as such can be called both with interrupts enabled or disabled. We
really dont want to accidentally set IF.

Therefore, use save/restore in preference to disable/enable.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

diff -r 076c3034c8c7 -r 1c3d2e4d06fe xen/arch/x86/crash.c
--- a/xen/arch/x86/crash.c      Mon Jun 13 17:45:43 2011 +0100
+++ b/xen/arch/x86/crash.c      Mon Jun 13 17:45:43 2011 +0100
@@ -55,9 +55,9 @@ static int crash_nmi_callback(struct cpu
 
 static void nmi_shootdown_cpus(void)
 {
-    unsigned long msecs;
+    unsigned long msecs, flags;
 
-    local_irq_disable();
+    local_irq_save(flags);
 
     crashing_cpu = smp_processor_id();
     local_irq_count(crashing_cpu) = 0;
@@ -80,7 +80,7 @@ static void nmi_shootdown_cpus(void)
     __stop_this_cpu();
     disable_IO_APIC();
 
-    local_irq_enable();
+    local_irq_restore(flags);
 }
 
 void machine_crash_shutdown(void)

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