The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bc715ee4dbc5db462c59b9cfba92d31b3274fe3a Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" rostedt@goodmis.org Date: Sun, 18 Nov 2018 17:35:37 -0500 Subject: [PATCH] sh/function_graph: Simplify with function_graph_enter()

The function_graph_enter() function does the work of calling the function graph hook function and the management of the shadow stack, simplifying the work done in the architecture dependent prepare_ftrace_return().

Have superh use the new code, and remove the shadow stack management as well as having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack is used.

Cc: Yoshinori Sato ysato@users.sourceforge.jp Cc: Rich Felker dalias@libc.org Cc: linux-sh@vger.kernel.org Cc: stable@kernel.org Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c index 96dd9f7da250..1b04270e5460 100644 --- a/arch/sh/kernel/ftrace.c +++ b/arch/sh/kernel/ftrace.c @@ -321,8 +321,7 @@ int ftrace_disable_ftrace_graph_caller(void) void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) { unsigned long old; - int faulted, err; - struct ftrace_graph_ent trace; + int faulted; unsigned long return_hooker = (unsigned long)&return_to_handler;

if (unlikely(ftrace_graph_is_dead())) @@ -365,18 +364,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) return; }

- err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL); - if (err == -EBUSY) { + if (function_graph_enter(old, self_addr, 0, NULL)) __raw_writel(old, parent); - return; - } - - trace.func = self_addr; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { - current->curr_ret_stack--; - __raw_writel(old, parent); - } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */