[PATCH v2] objtool/x86: add missing embedded_insn check

[PATCH v2] objtool/x86: add missing embedded_insn check

[John Sperbeck]

When dbf460087755 ("objtool/x86: Fixup frame-pointer vs rethunk")
was backported to some stable branches, the check for dest->embedded_insn
in is_special_call() was missed.  The result is that the warning it
was intended to suppress still appears.  For example on 6.1 (on kernels
before 6.1, the '-s' argument would instead be 'check'):

$ tools/objtool/objtool -s arch/x86/lib/retpoline.o
arch/x86/lib/retpoline.o: warning: objtool: srso_untrain_ret+0xd:
    call without frame pointer save/setup

With this patch, the warning is correctly suppressed, and the
kernel still passes the normal Google kernel developer tests.

Signed-off-by: John Sperbeck <jsperbeck@google.com>
---

I think 6.1.y, 5.15.y, and 5.10.y are the LTS branches missing the
bit of code that this patch re-adds.

Changes from v1 to v2:
* include more context in the commit message.


 tools/objtool/check.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f8008ab31eef..cb363b507a32 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2478,7 +2478,7 @@ static bool is_special_call(struct instruction *insn)
 		if (!dest)
 			return false;
 
-		if (dest->fentry)
+		if (dest->fentry || dest->embedded_insn)
 			return true;
 	}
 
-- 
2.42.0.820.g83a721a137-goog

Re: [PATCH v2] objtool/x86: add missing embedded_insn check

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCH v2] objtool/x86: add missing embedded_insn check
Link: https://lore.kernel.org/stable/20231028184131.2103810-1-jsperbeck%40google.com

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki