bd604f3db4
Song Shuai reported: The list func (ftrace_ops_list_func) will be patched first before the transition between old and new calls are set, which fixed the race described in this commit `59338f75`. While ftrace_trace_function changes from the list func to a ftrace_ops func, like unregistering the klp_ops to leave the only global_ops in ftrace_ops_list, the ftrace_[regs]_call will be replaced with the list func although it already exists. So there should be a condition to avoid this. And suggested using another variable to keep track of what the ftrace function is set to. But this could be simplified by using a helper function that does the same with a static variable. Link: https://lore.kernel.org/lkml/20221026132039.2236233-1-suagrfillet@gmail.com/ Link: https://lore.kernel.org/linux-trace-kernel/20221122180905.737b6f52@gandalf.local.home Reported-by: Song Shuai <suagrfillet@gmail.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>