From: Aaron Tomlin <atomlin@xxxxxxxxxx>
This patch introduces the x86 specific implementation
changes to the arch_trigger_all_cpu_backtrace() routine.
Now users have the ability to choose whether or not to
issue an NMI back trace which includes current.
[Don't print message in single processor case,
wrap with get/put_cpu based on Oleg's suggestion -dcz]
Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxx>
Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx>
---
arch/x86/include/asm/irq.h | 2 +-
arch/x86/kernel/apic/hw_nmi.c | 17 +++++++++++++----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index cb6cfcd..a80cbb8 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -43,7 +43,7 @@ extern int vector_used_by_percpu_irq(unsigned int vector);
extern void init_ISA_irqs(void);
#ifdef CONFIG_X86_LOCAL_APIC
-void arch_trigger_all_cpu_backtrace(void);
+void arch_trigger_all_cpu_backtrace(bool);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
#endif
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index a698d71..1400d72 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -33,31 +33,40 @@ static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
/* "in progress" flag of arch_trigger_all_cpu_backtrace */
static unsigned long backtrace_flag;
-void arch_trigger_all_cpu_backtrace(void)
+void arch_trigger_all_cpu_backtrace(bool include_self)
{
int i;
+ int cpu = get_cpu();
- if (test_and_set_bit(0, &backtrace_flag))
+ if (test_and_set_bit(0, &backtrace_flag)) {
/*
* If there is already a trigger_all_cpu_backtrace() in progress
* (backtrace_flag == 1), don't output double cpu dump infos.
*/
+ put_cpu();
return;
+ }
cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+ if (!include_self)
+ cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
- printk(KERN_INFO "sending NMI to all CPUs:\n");
- apic->send_IPI_all(NMI_VECTOR);
+ if (!cpumask_empty(to_cpumask(backtrace_mask))) {
+ pr_info("sending NMI to %s CPUs:\n", (include_self ? "all" : "other"));
+ apic->send_IPI_mask(to_cpumask(backtrace_mask), NMI_VECTOR);
+ }
/* Wait for up to 10 seconds for all CPUs to do the backtrace */
for (i = 0; i < 10 * 1000; i++) {
if (cpumask_empty(to_cpumask(backtrace_mask)))
break;
mdelay(1);
+ touch_softlockup_watchdog();
}
clear_bit(0, &backtrace_flag);
smp_mb__after_clear_bit();
+ put_cpu();
}
static int __kprobes
--
1.7.1
--
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