Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, vm86: fix preemption bug
  x86, olpc: fix model detection without OFW
  x86, hpet: fix for LS21 + HPET = boot hang
  x86: CPA avoid repeated lazy mmu flush
  x86: warn if arch_flush_lazy_mmu_cpu is called in preemptible context
  x86/paravirt: make arch_flush_lazy_mmu/cpu disable preemption
  x86, pat: fix warn_on_once() while mapping 0-1MB range with /dev/mem
  x86/cpa: make sure cpa is safe to call in lazy mmu mode
  x86, ptrace, mm: fix double-free on race

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 7932338d7cb3..a9e7548e1790 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -99,6 +99,12 @@ static inline void preempt_conditional_sti(struct pt_regs *regs)
                 local_irq_enable();
 }
 
+static inline void conditional_cli(struct pt_regs *regs)
+{
+        if (regs->flags & X86_EFLAGS_IF)
+                local_irq_disable();
+}
+
 static inline void preempt_conditional_cli(struct pt_regs *regs)
 {
         if (regs->flags & X86_EFLAGS_IF)
@@ -626,8 +632,10 @@ clear_dr7:
 
 #ifdef CONFIG_X86_32
 debug_vm86:
+        /* reenable preemption: handle_vm86_trap() might sleep */
+        dec_preempt_count();
         handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
-        preempt_conditional_cli(regs);
+        conditional_cli(regs);
         return;
 #endif