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>

arch/arm/kernel/stacktrace.c

@@ -66,4 +66,5 @@ void save_stack_trace(struct stack_trace *trace)
 
 	walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);
 #endif

arch/avr32/kernel/stacktrace.c

@@ -51,3 +51,4 @@ void save_stack_trace(struct stack_trace *trace)
 		fp = frame->fp;
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);

arch/mips/kernel/stacktrace.c

@@ -73,3 +73,4 @@ void save_stack_trace(struct stack_trace *trace)
 	prepare_frametrace(regs);
 	save_context_stack(trace, regs);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);

arch/powerpc/kernel/stacktrace.c

@@ -44,3 +44,4 @@ void save_stack_trace(struct stack_trace *trace)
 		sp = newsp;
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);

arch/s390/kernel/stacktrace.c

@@ -81,6 +81,7 @@ void save_stack_trace(struct stack_trace *trace)
 			   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 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);

arch/sh/kernel/stacktrace.c

@@ -34,3 +34,4 @@ void save_stack_trace(struct stack_trace *trace)
 		}
 	}
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);

arch/sparc64/kernel/stacktrace.c

@@ -47,3 +47,4 @@ void save_stack_trace(struct stack_trace *trace)
 			trace->entries[trace->nr_entries++] = pc;
 	} while (trace->nr_entries < trace->max_entries);
 }
+EXPORT_SYMBOL_GPL(save_stack_trace);