Commit-ID:  cfee9eddcd61e28b73468647fc4aa7ff2d706254
Gitweb:     http://git.kernel.org/tip/cfee9eddcd61e28b73468647fc4aa7ff2d706254
Author:     Josh Poimboeuf <[email protected]>
AuthorDate: Thu, 6 Oct 2016 00:28:40 -0500
Committer:  Ingo Molnar <[email protected]>
CommitDate: Thu, 6 Oct 2016 09:52:20 +0200

x86/unwind: Fix oprofile module link error

When compiling on x86 with CONFIG_OPROFILE=m and CONFIG_FRAME_POINTER=n,
the oprofile module fails to link:

  ERROR: ftrace_graph_ret_addr" [arch/x86/oprofile/oprofile.ko] undefined!

The problem was introduced when oprofile was converted to use the new
x86 unwinder.  When frame pointers are disabled, the "guess" unwinder's
unwind_get_return_address() is an inline function which calls
ftrace_graph_ret_addr(), which is not exported.

Fix it by converting the "guess" version of unwind_get_return_address()
to an exported out-of-line function, just like its frame pointer
counterpart.

Reported-by: Karl Beldan <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: ec2ad9ccf12d ("oprofile/x86: Convert x86_backtrace() to use the new 
unwinder")
Link: 
http://lkml.kernel.org/r/be08d589f6474df78364e081c42777e382af9352.1475731632.git.jpoim...@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/include/asm/unwind.h  | 14 ++------------
 arch/x86/kernel/unwind_guess.c | 10 ++++++++++
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index c4b6d1c..46de9ac 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -23,6 +23,8 @@ void __unwind_start(struct unwind_state *state, struct 
task_struct *task,
 
 bool unwind_next_frame(struct unwind_state *state);
 
+unsigned long unwind_get_return_address(struct unwind_state *state);
+
 static inline bool unwind_done(struct unwind_state *state)
 {
        return state->stack_info.type == STACK_TYPE_UNKNOWN;
@@ -48,8 +50,6 @@ unsigned long *unwind_get_return_address_ptr(struct 
unwind_state *state)
        return state->bp + 1;
 }
 
-unsigned long unwind_get_return_address(struct unwind_state *state);
-
 #else /* !CONFIG_FRAME_POINTER */
 
 static inline
@@ -58,16 +58,6 @@ unsigned long *unwind_get_return_address_ptr(struct 
unwind_state *state)
        return NULL;
 }
 
-static inline
-unsigned long unwind_get_return_address(struct unwind_state *state)
-{
-       if (unwind_done(state))
-               return 0;
-
-       return ftrace_graph_ret_addr(state->task, &state->graph_idx,
-                                    *state->sp, state->sp);
-}
-
 #endif /* CONFIG_FRAME_POINTER */
 
 #endif /* _ASM_X86_UNWIND_H */
diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
index b5a834c..9298993 100644
--- a/arch/x86/kernel/unwind_guess.c
+++ b/arch/x86/kernel/unwind_guess.c
@@ -5,6 +5,16 @@
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
 
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+       if (unwind_done(state))
+               return 0;
+
+       return ftrace_graph_ret_addr(state->task, &state->graph_idx,
+                                    *state->sp, state->sp);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
 bool unwind_next_frame(struct unwind_state *state)
 {
        struct stack_info *info = &state->stack_info;

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