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-rw-r--r--arch/arm/kernel/smp.c9
-rw-r--r--lib/nmi_backtrace.c11
2 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7c467c5b048e..b26361355dae 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -749,6 +749,15 @@ core_initcall(register_cpufreq_notifier);
static void raise_nmi(cpumask_t *mask)
{
+ /*
+ * Generate the backtrace directly if we are running in a calling
+ * context that is not preemptible by the backtrace IPI. Note
+ * that nmi_cpu_backtrace() automatically removes the current cpu
+ * from mask.
+ */
+ if (cpumask_test_cpu(smp_processor_id(), mask) && irqs_disabled())
+ nmi_cpu_backtrace(NULL);
+
smp_cross_call(mask, IPI_CPU_BACKTRACE);
}
diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index 88d3d32e5923..6019c53c669e 100644
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -43,6 +43,12 @@ static void print_seq_line(struct nmi_seq_buf *s, int start, int end)
printk("%.*s", (end - start) + 1, buf);
}
+/*
+ * When raise() is called it will be is passed a pointer to the
+ * backtrace_mask. Architectures that call nmi_cpu_backtrace()
+ * directly from their raise() functions may rely on the mask
+ * they are passed being updated as a side effect of this call.
+ */
void nmi_trigger_all_cpu_backtrace(bool include_self,
void (*raise)(cpumask_t *mask))
{
@@ -149,7 +155,10 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
/* Replace printk to write into the NMI seq */
this_cpu_write(printk_func, nmi_vprintk);
pr_warn("NMI backtrace for cpu %d\n", cpu);
- show_regs(regs);
+ if (regs)
+ show_regs(regs);
+ else
+ dump_stack();
this_cpu_write(printk_func, printk_func_save);
cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));