From 9ab181fa9ff73a38fccd0a4f1c40a38dfe62b535 Mon Sep 17 00:00:00 2001 From: Don Zickus Date: Tue, 4 Jan 2011 22:38:07 -0500 Subject: [PATCH] x86: Only call smp_processor_id in non-preempt cases There are some paths that walk the die_chain with preemption on. Make sure we are in an NMI call before we start doing anything. This was triggered by do_general_protection calling notify_die with DIE_GPF. Reported-by: Jan Kiszka Signed-off-by: Don Zickus LKML-Reference: <1294198689-15447-1-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/hw_nmi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c index c57d0b5..2b40a60 100644 --- a/arch/x86/kernel/apic/hw_nmi.c +++ b/arch/x86/kernel/apic/hw_nmi.c @@ -51,7 +51,7 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self, { struct die_args *args = __args; struct pt_regs *regs; - int cpu = smp_processor_id(); + int cpu; switch (cmd) { case DIE_NMI: @@ -63,6 +63,7 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self, } regs = args->regs; + cpu = smp_processor_id(); if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; -- 2.7.4