Re: [for-linus][PATCH 1/3] x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up

Peter Zijlstra
2020-05-18T08:01:31Z

On Thu, May 14, 2020 at 08:58:18AM -0400, Steven Rostedt wrote:
> + start_offset = (unsigned long)ftrace_caller;
> + end_offset = (unsigned long)ftrace_epilogue;

---
Subject: x86/ftrace: Fix compile error

When building x86-64 kernels, my compiler is sad about a missing symbol.

Fixes: 59566b0b622e ("x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/ftrace.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index f8917a6f25b7..1cf7d69402e2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -286,6 +286,7 @@ extern void ftrace_regs_caller_ret(void);
extern void ftrace_caller_end(void);
extern void ftrace_caller_op_ptr(void);
extern void ftrace_regs_caller_op_ptr(void);
+extern void ftrace_epilogue(void);

/* movq function_trace_op(%rip), %rdx */
/* 0x48 0x8b 0x15 <offset-to-ftrace_trace_op (4 bytes)> */