[PATCH AUTOSEL 4.20 42/52] csky: Fixup dead loop in show_stack

[Sasha Levin]

From: Guo Ren <ren_guo@xxxxxxxxx>

[ Upstream commit 131aee8b9807bc98379fa5a0270389dbc7dcec90 ]

When STACKTRACE is enabled, we must pass fp as stack for unwind,
otherwise random value in stack will casue a dead loop.

Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
Reported-by: Lu Baoquan <lu.baoquan@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/csky/kernel/dumpstack.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c
index a9a03ac57ec5..28d2deb0848d 100644
--- a/arch/csky/kernel/dumpstack.c
+++ b/arch/csky/kernel/dumpstack.c
@@ -47,7 +47,11 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		if (task)
 			stack = (unsigned long *)task->thread.esp0;
 		else
+#ifdef CONFIG_STACKTRACE
+			asm volatile("mov %0, r8\n":"=r"(stack)::"memory");
+#else
 			stack = (unsigned long *)&stack;
+#endif
 	}
 	endstack = (unsigned long *)
 		(((unsigned long)stack + THREAD_SIZE - 1) & -THREAD_SIZE);
-- 
2.19.1