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Patch "kernel/extable.c: mark core_kernel_text notrace" has been added to the 3.18-stable tree

PATCH [email protected] 1 participant 1 message Jul 18, 2017 Stable branch

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

kernel/extable.c: mark core_kernel_text notrace

to the 3.18-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:
kernel-extable.c-mark-core_kernel_text-notrace.patch
and it can be found in the queue-3.18 subdirectory.

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

Quoted 1 line

From c0d80ddab89916273cb97114889d3f337bc370ae Mon Sep 17 00:00:00 2001

From: Marcin Nowakowski <[email protected]>
Date: Thu, 6 Jul 2017 15:35:31 -0700
Subject: kernel/extable.c: mark core_kernel_text notrace

From: Marcin Nowakowski <[email protected]>

commit c0d80ddab89916273cb97114889d3f337bc370ae upstream.

core_kernel_text is used by MIPS in its function graph trace processing, so having this method traced leads to an infinite set of recursive calls such as:

  Call Trace:
     ftrace_return_to_handler+0x50/0x128
     core_kernel_text+0x10/0x1b8
     prepare_ftrace_return+0x6c/0x114
     ftrace_graph_caller+0x20/0x44
     return_to_handler+0x10/0x30
     return_to_handler+0x0/0x30
     return_to_handler+0x0/0x30
     ftrace_ops_no_ops+0x114/0x1bc
     core_kernel_text+0x10/0x1b8
     core_kernel_text+0x10/0x1b8
     core_kernel_text+0x10/0x1b8
     ftrace_ops_no_ops+0x114/0x1bc
     core_kernel_text+0x10/0x1b8
     prepare_ftrace_return+0x6c/0x114
     ftrace_graph_caller+0x20/0x44
     (...)

Mark the function notrace to avoid it being traced.

Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Marcin Nowakowski <[email protected]>
Reviewed-by Masami Hiramatsu <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Meyer <[email protected]>
Cc Ingo Molnar <[email protected]>
Cc Steven Rostedt <[email protected]>
Cc Daniel Borkmann <[email protected]>
Cc Paul Gortmaker <[email protected]>
Cc Thomas Gleixner <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 kernel/extable.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
kernel/extable.c +1 -1
@@ -66,7 +66,7 @@ static inline int init_kernel_text(unsig
 	return 0;
 }
 
-int core_kernel_text(unsigned long addr)
+int notrace core_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_stext &&
 	    addr < (unsigned long)_etext)

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

queue-3.18/kernel-extable.c-mark-core_kernel_text-notrace.patch