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Commit 1714f9bf authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
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[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: default avatarAndi Kleen <ak@suse.de>
parent 08269c6d

arch/i386/kernel/nmi.c

+5 −4
Original line number Diff line number Diff line
@@ -41,16 +41,17 @@ int nmi_watchdog_enabled; 
 *   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

arch/x86_64/kernel/nmi.c

+6 −4
Original line number Diff line number Diff line
@@ -39,15 +39,17 @@ int panic_on_unrecovered_nmi; 
 *   different subsystems this reservation system just tries to coordinate

 *   things a little

 */

static DEFINE_PER_CPU(unsigned, perfctr_nmi_owner);

static DEFINE_PER_CPU(unsigned, evntsel_nmi_owner[2]);



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, perfctr_nmi_owner[NMI_MAX_COUNTER_LONGS]);

static DEFINE_PER_CPU(unsigned, 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