Patch "ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-8668-1-ftrace-fix-dynamic-ftrace-with-debug_rodata-and-frame_pointer.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Abel Vesa <[email protected]>
Date: Mon, 3 Apr 2017 23:58:54 +0100
Subject: ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER

From: Abel Vesa <[email protected]>

[ Upstream commit 6f05d0761af612e04572ba4d65b4c0274a88444f ]

The support for dynamic ftrace with CONFIG_DEBUG_RODATA involves overriding the weak arch_ftrace_update_code() with a variant which makes the kernel text writable around the patching.

This override was however added under the CONFIG_OLD_MCOUNT ifdef, and CONFIG_OLD_MCOUNT is only enabled if frame pointers are enabled.

This leads to non-functional dynamic ftrace (ftrace triggers a WARN_ON()) when CONFIG_DEBUG_RODATA is enabled and CONFIG_FRAME_POINTER is not.

Move the override out of that ifdef and into the CONFIG_DYNAMIC_FTRACE ifdef where it belongs.

---
 arch/arm/kernel/ftrace.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

@@ -29,11 +29,6 @@
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-#ifdef CONFIG_OLD_MCOUNT
-#define OLD_MCOUNT_ADDR	((unsigned long) mcount)
-#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
-
-#define	OLD_NOP		0xe1a00000	/* mov r0, r0 */
 
 static int __ftrace_modify_code(void *data)
 {

@@ -51,6 +46,12 @@ void arch_ftrace_update_code(int command
 	stop_machine(__ftrace_modify_code, &command, NULL);
 }
 
+#ifdef CONFIG_OLD_MCOUNT
+#define OLD_MCOUNT_ADDR	((unsigned long) mcount)
+#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
+
+#define	OLD_NOP		0xe1a00000	/* mov r0, r0 */
+
 static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
 {
 	return rec->arch.old_mcount ? OLD_NOP : NOP;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/arm-8668-1-ftrace-fix-dynamic-ftrace-with-debug_rodata-and-frame_pointer.patch