Merge commit 'tip/perfcounters-for-linus' into oprofile/master

Conflicts:
	arch/x86/oprofile/op_model_ppro.c

Signed-off-by: Robert Richter <robert.richter@amd.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index 0a261a5c696e..cd72d5c73b49 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -118,6 +118,13 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
         u64 val;
         int i;
 
+        /*
+         * This can happen if perf counters are in use when
+         * we steal the die notifier NMI.
+         */
+        if (unlikely(!reset_value))
+                goto out;
+
         for (i = 0 ; i < num_counters; ++i) {
                 if (!reset_value[i])
                         continue;
@@ -128,6 +135,7 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
                 wrmsrl(msrs->counters[i].addr, -reset_value[i]);
         }
 
+out:
         /* Only P6 based Pentium M need to re-unmask the apic vector but it
          * doesn't hurt other P6 variant */
         apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED);