[PATCH] objtool: fix STACK_FRAME_NON_STANDARD macro checking for function symbols

[Josh Poimboeuf]

Mathieu Desnoyers reported that the STACK_FRAME_NON_STANDARD macro
wasn't working with the lttng_filter_interpret_bytecode() function in
the lttng-modules code.

Usually the relocation created by STACK_FRAME_NON_STANDARD creates a
reference to a section symbol like this:

  Offset              Type            Value               Addend Name
  000000000000000000  X86_64_64       000000000000000000   +3136 .text

But in this case it created a reference to a function symbol:

  Offset              Type            Value               Addend Name
  000000000000000000  X86_64_64       0x00000000000003a0      +0 
lttng_filter_interpret_bytecode

To be honest I have no idea what causes gcc to decide to do one over the
other.  But both are valid ELF, so add support for the function symbol.

Reported-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
 tools/objtool/builtin-check.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index e8a1e69..25d8031 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -122,10 +122,14 @@ static bool ignore_func(struct objtool_file *file, struct 
symbol *func)
 
        /* check for STACK_FRAME_NON_STANDARD */
        if (file->whitelist && file->whitelist->rela)
-               list_for_each_entry(rela, &file->whitelist->rela->rela_list, 
list)
-                       if (rela->sym->sec == func->sec &&
+               list_for_each_entry(rela, &file->whitelist->rela->rela_list, 
list) {
+                       if (rela->sym->type == STT_SECTION &&
+                           rela->sym->sec == func->sec &&
                            rela->addend == func->offset)
                                return true;
+                       if (rela->sym->type == STT_FUNC && rela->sym == func)
+                               return true;
+               }
 
        /* check if it has a context switching instruction */
        func_for_each_insn(file, func, insn)
-- 
2.4.11