FAILED: patch "[PATCH] function_graph: Create function_graph_enter() to consolidate" failed to apply to 4.4-stable tree

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

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Stable branch Tracing ftrace

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2018-12-03 14:32 UTC #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 8114865ff82e200b383e46821c25cb0625b842b5 Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" <[email protected]>
Date: Sun, 18 Nov 2018 17:10:15 -0500
Subject: [PATCH] function_graph: Create function_graph_enter() to consolidate
architecture code

Currently all the architectures do basically the same thing in preparing the function graph tracer on entry to a function. This code can be pulled into a generic location and then this will allow the function graph tracer to be fixed, as well as extended.

Create a new function graph helper function_graph_enter() that will call the hook function (ftrace_graph_entry) and the shadow stack operation (ftrace_push_return_trace), and remove the need of the architecture code to manage the shadow stack.

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

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]>

include/linux/ftrace.h +3 -0

index a397907e8d72..5717e8f81c59 100644
@@ -779,6 +779,9 @@ extern void return_to_handler(void);
 extern int
 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 			 unsigned long frame_pointer, unsigned long *retp);
+extern int
+function_graph_enter(unsigned long ret, unsigned long func,
+		     unsigned long frame_pointer, unsigned long *retp);
 
 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 				    unsigned long ret, unsigned long *retp);

kernel/trace/trace_functions_graph.c +16 -0

index 169b3c44ee97..28f2602435d0 100644
@@ -182,6 +182,22 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 	return 0;
 }
 
+int function_graph_enter(unsigned long ret, unsigned long func,
+			 unsigned long frame_pointer, unsigned long *retp)
+{
+	struct ftrace_graph_ent trace;
+
+	trace.func = func;
+	trace.depth = current->curr_ret_stack + 1;
+
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace))
+		return -EBUSY;
+
+	return ftrace_push_return_trace(ret, func, &trace.depth,
+					frame_pointer, retp);
+}
+
 /* Retrieve a function return address to the trace stack on thread info.*/
 static void
 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,