Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[linux-2.6-block.git] / lib / nmi_backtrace.c

diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index 5f7999eacad5dacf48ec41632916113409e3681d..0bc0a3535a8acb6e66c7235c934beadf49262194 100644 (file)
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -17,6 +17,7 @@
 #include <linux/kprobes.h>
 #include <linux/nmi.h>
 #include <linux/cpu.h>
+#include <linux/sched/debug.h>
 
 #ifdef arch_trigger_cpumask_backtrace
 /* For reliability, we're prepared to waste bits here. */
@@ -85,9 +86,11 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
 
 bool nmi_cpu_backtrace(struct pt_regs *regs)
 {
+       static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
        int cpu = smp_processor_id();
 
        if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
+               arch_spin_lock(&lock);
                if (regs && cpu_in_idle(instruction_pointer(regs))) {
                        pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n",
                                cpu, instruction_pointer(regs));
@@ -98,6 +101,7 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
                        else
                                dump_stack();
                }
+               arch_spin_unlock(&lock);
                cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
                return true;
        }