diff options
Diffstat (limited to 'arch/x86/kernel/traps.c')
| -rw-r--r-- | arch/x86/kernel/traps.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 23f6ac05d04c..613b3d284a89 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -84,6 +84,11 @@ EXPORT_SYMBOL_GPL(used_vectors); static int ignore_nmis; int unknown_nmi_panic; +/* + * Prevent NMI reason port (0x61) being accessed simultaneously, can + * only be used in NMI handler. + */ +static DEFINE_RAW_SPINLOCK(nmi_reason_lock); static inline void conditional_sti(struct pt_regs *regs) { @@ -392,7 +397,6 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs) static notrace __kprobes void default_do_nmi(struct pt_regs *regs) { unsigned char reason = 0; - int cpu; /* * CPU-specific NMI must be processed before non-CPU-specific @@ -402,13 +406,12 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) return; - cpu = smp_processor_id(); - - /* Only the BSP gets external NMIs from the system. */ - if (!cpu) - reason = get_nmi_reason(); + /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */ + raw_spin_lock(&nmi_reason_lock); + reason = get_nmi_reason(); if (!(reason & NMI_REASON_MASK)) { + raw_spin_unlock(&nmi_reason_lock); unknown_nmi_error(reason, regs); return; @@ -426,6 +429,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) */ reassert_nmi(); #endif + raw_spin_unlock(&nmi_reason_lock); } dotraplinkage notrace __kprobes void |