arm64: prep stack walkers for THREAD_INFO_IN_TASK

[karo-tx-linux.git] / arch / arm64 / kernel / process.c

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 01753cd7d3f01d3551568d64612bd5a14843ac18..ec7b9c00effe1b3fcbb1d8cfbdc91c7f92d261ab 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -350,27 +350,35 @@ struct task_struct *__switch_to(struct task_struct *prev,
 unsigned long get_wchan(struct task_struct *p)
 {
        struct stackframe frame;
-       unsigned long stack_page;
+       unsigned long stack_page, ret = 0;
        int count = 0;
        if (!p || p == current || p->state == TASK_RUNNING)
                return 0;
 
+       stack_page = (unsigned long)try_get_task_stack(p);
+       if (!stack_page)
+               return 0;
+
        frame.fp = thread_saved_fp(p);
        frame.sp = thread_saved_sp(p);
        frame.pc = thread_saved_pc(p);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
        frame.graph = p->curr_ret_stack;
 #endif
-       stack_page = (unsigned long)task_stack_page(p);
        do {
                if (frame.sp < stack_page ||
                    frame.sp >= stack_page + THREAD_SIZE ||
                    unwind_frame(p, &frame))
-                       return 0;
-               if (!in_sched_functions(frame.pc))
-                       return frame.pc;
+                       goto out;
+               if (!in_sched_functions(frame.pc)) {
+                       ret = frame.pc;
+                       goto out;
+               }
        } while (count ++ < 16);
-       return 0;
+
+out:
+       put_task_stack(p);
+       return ret;
 }
 
 unsigned long arch_align_stack(unsigned long sp)