stacktrace: export save_stack_trace[_tsk]

Andrew Morton reported this against linux-next:

ERROR: ".save_stack_trace" [tests/backtracetest.ko] undefined!

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index ae31deb..6b3ffde 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -66,4 +66,5 @@
 
 	walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
 #endif
diff --git a/arch/avr32/kernel/stacktrace.c b/arch/avr32/kernel/stacktrace.c
index 9a68190..f4bdb44 100644
--- a/arch/avr32/kernel/stacktrace.c
+++ b/arch/avr32/kernel/stacktrace.c
@@ -51,3 +51,4 @@
 		fp = frame->fp;
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
diff --git a/arch/mips/kernel/stacktrace.c b/arch/mips/kernel/stacktrace.c
index ebd9db8..5eb4681 100644
--- a/arch/mips/kernel/stacktrace.c
+++ b/arch/mips/kernel/stacktrace.c
@@ -73,3 +73,4 @@
 	prepare_frametrace(regs);
 	save_context_stack(trace, regs);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index 9629440..9861f17 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -44,3 +44,4 @@
 		sp = newsp;
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 85e46a5..57571f1 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -81,6 +81,7 @@
 			   S390_lowcore.thread_info,
 			   S390_lowcore.thread_info + THREAD_SIZE, 1);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
@@ -93,3 +94,4 @@
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
diff --git a/arch/sh/kernel/stacktrace.c b/arch/sh/kernel/stacktrace.c
index d41e561..1b2ae35 100644
--- a/arch/sh/kernel/stacktrace.c
+++ b/arch/sh/kernel/stacktrace.c
@@ -34,3 +34,4 @@
 		}
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index c73ce3f..49656ed 100644
--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -47,3 +47,4 @@
 			trace->entries[trace->nr_entries++] = pc;
 	} while (trace->nr_entries < trace->max_entries);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);