[PATCH] x86: Fix potential overflow in perfctr reservation
While reviewing this code again I found a potential overflow of the bitmap.
The p4 oprofile can theoretically set bits beyond the reservation bitmap for
specific configurations. Avoid that by sizing the bitmaps properly.
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index a98ba88..9f1e8c1 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -41,16 +41,17 @@
* different subsystems this reservation system just tries to coordinate
* things a little
*/
-static DEFINE_PER_CPU(unsigned long, perfctr_nmi_owner);
-static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]);
-
-static cpumask_t backtrace_mask = CPU_MASK_NONE;
/* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
* offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now)
*/
#define NMI_MAX_COUNTER_BITS 66
+#define NMI_MAX_COUNTER_LONGS BITS_TO_LONGS(NMI_MAX_COUNTER_BITS)
+static DEFINE_PER_CPU(unsigned long, perfctr_nmi_owner[NMI_MAX_COUNTER_LONGS]);
+static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[NMI_MAX_COUNTER_LONGS]);
+
+static cpumask_t backtrace_mask = CPU_MASK_NONE;
/* nmi_active:
* >0: the lapic NMI watchdog is active, but can be disabled
* <0: the lapic NMI watchdog has not been set up, and cannot