1 files changed, 31 insertions, 2 deletions

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index d9751a4769e7..8a552a33c6ef 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -22,6 +22,7 @@
 #include <linux/stacktrace.h>
 
 #include <asm/irq.h>
+#include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
 /*
@@ -43,6 +44,9 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 	unsigned long fp = frame->fp;
 	unsigned long irq_stack_ptr;
 
+	if (!tsk)
+		tsk = current;
+
 	/*
 	 * Switching between stacks is valid when tracing current and in
 	 * non-preemptible context.
@@ -67,7 +71,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 	frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	if (tsk && tsk->ret_stack &&
+	if (tsk->ret_stack &&
 			(frame->pc == (unsigned long)return_to_handler)) {
 		/*
 		 * This is a case where function graph tracer has
@@ -125,7 +129,6 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
 			break;
 	}
 }
-EXPORT_SYMBOL(walk_stackframe);
 
 #ifdef CONFIG_STACKTRACE
 struct stack_trace_data {
@@ -152,11 +155,35 @@ static int save_trace(struct stackframe *frame, void *d)
 	return trace->nr_entries >= trace->max_entries;
 }
 
+void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+	struct stack_trace_data data;
+	struct stackframe frame;
+
+	data.trace = trace;
+	data.skip = trace->skip;
+	data.no_sched_functions = 0;
+
+	frame.fp = regs->regs[29];
+	frame.sp = regs->sp;
+	frame.pc = regs->pc;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	frame.graph = current->curr_ret_stack;
+#endif
+
+	walk_stackframe(current, &frame, save_trace, &data);
+	if (trace->nr_entries < trace->max_entries)
+		trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
 	struct stack_trace_data data;
 	struct stackframe frame;
 
+	if (!try_get_task_stack(tsk))
+		return;
+
 	data.trace = trace;
 	data.skip = trace->skip;
 
@@ -178,6 +205,8 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 	walk_stackframe(tsk, &frame, save_trace, &data);
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
+
+	put_task_stack(tsk);
 }
 
 void save_stack_trace(struct stack_trace *trace)