arm64: fix dump_backtrace/unwind_frame with NULL tsk

[deliverable/linux.git] / arch / arm64 / kernel / stacktrace.c

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index d9751a4769e758b220181d6a400bd5a238c2cedb..d34fd72172b6fd6490ec2824e52dfef1cf33a8c9 100644 (file)
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -43,6 +43,9 @@ 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 +70,7 @@ 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