Commit 9ab181fa authored Jan 04, 2011 by Don Zickus Committed by Ingo Molnar Jan 05, 2011

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 <jan.kiszka@web.de>
Signed-off-by: Don Zickus <dzickus@redhat.com>
LKML-Reference: <1294198689-15447-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent aef1b9ce

arch/x86/kernel/apic/hw_nmi.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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;