Skip to contentSkip to conversation

FAILED: patch "[PATCH] ARM: function_graph: Simplify with function_graph_enter()" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Dec 3, 2018

Subsystems (3)
Stable branch Arm (32-bit) ftrace
lore
Share & tools
lore

[email protected]

author maintainer
#0 lore raw

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 <[email protected]>.

thanks,

greg k-h

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

Quoted 1 line

From f1f5b14afd7cce39e6a9b25c685e1ea34c231096 Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" <[email protected]>
Date: Sun, 18 Nov 2018 17:19:26 -0500
Subject: [PATCH] ARM: 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 ARM 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 Russell King <[email protected]>
Cc [email protected]
Cc [email protected]
Fixes 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by Masami Hiramatsu <[email protected]>
Signed-off-by Steven Rostedt (VMware) <[email protected]>
arch/arm/kernel/ftrace.c +1 -16
index 0142fcfcc3d3..bda949fd84e8 100644
@@ -183,9 +183,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
 			   unsigned long frame_pointer)
 {
 	unsigned long return_hooker = (unsigned long) &return_to_handler;
-	struct ftrace_graph_ent trace;
 	unsigned long old;
-	int err;
 
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;

@@ -193,21 +191,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
 	old = *parent;
 	*parent = return_hooker;
 
-	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, NULL))
 		*parent = old;
-		return;
-	}
-
-	err = ftrace_push_return_trace(old, self_addr, &trace.depth,
-				       frame_pointer, NULL);
-	if (err == -EBUSY) {
-		*parent = old;
-		return;
-	}
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE