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 9c4bf5e0db164f330a2d3e128e9832661f69f0e9 Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" rostedt@goodmis.org Date: Sun, 18 Nov 2018 17:37:40 -0500 Subject: [PATCH] sparc/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 sparc 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: "David S. Miller" davem@davemloft.net Cc: sparclinux@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/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c index 915dda4ae412..684b84ce397f 100644 --- a/arch/sparc/kernel/ftrace.c +++ b/arch/sparc/kernel/ftrace.c @@ -126,20 +126,11 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long frame_pointer) { unsigned long return_hooker = (unsigned long) &return_to_handler; - struct ftrace_graph_ent trace;

if (unlikely(atomic_read(&current->tracing_graph_pause))) return parent + 8UL;

- trace.func = self_addr; - trace.depth = current->curr_ret_stack + 1; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - return parent + 8UL; - - if (ftrace_push_return_trace(parent, self_addr, &trace.depth, - frame_pointer, NULL) == -EBUSY) + if (function_graph_enter(parent, self_addr, frame_pointer, NULL)) return parent + 8UL;

return return_hooker;