4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
commit 07f7175b43827640d1e69c9eded89aa089a234b4 upstream.
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 x86 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: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: stable@xxxxxxxxxx
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/ftrace.c | 15 +--------------
1 file changed, 1 insertion(+), 14 deletions(-)
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -994,7 +994,6 @@ void prepare_ftrace_return(unsigned long
{
unsigned long old;
int faulted;
- struct ftrace_graph_ent trace;
unsigned long return_hooker = (unsigned long)
&return_to_handler;
@@ -1046,19 +1045,7 @@ void prepare_ftrace_return(unsigned long
return;
}
- trace.func = self_addr;
- trace.depth = current->curr_ret_stack + 1;
-
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace)) {
+ if (function_graph_enter(old, self_addr, frame_pointer, parent))
*parent = old;
- return;
- }
-
- if (ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer, parent) == -EBUSY) {
- *parent = old;
- return;
- }
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
