Re: linux-next: Tree for May 2 (objtool bug!)

From: Josh Poimboeuf
Date: Wed May 02 2018 - 17:06:36 EST


On Wed, May 02, 2018 at 08:59:38AM -0700, Randy Dunlap wrote:
> On 05/02/2018 08:43 AM, Josh Poimboeuf wrote:
> > On Wed, May 02, 2018 at 08:37:53AM -0700, Randy Dunlap wrote:
> >> On 05/01/2018 11:59 PM, Stephen Rothwell wrote:
> >>> Hi all,
> >>>
> >>> Changes since 20180501:
> >>>
> >>
> >> on x86_64 randconfig:
> >>
> >> CC fs/cifs/smbencrypt.o
> >> drivers/char/ipmi/ipmi_ssif.o: warning: objtool: return_hosed_msg()+0x0: infinite recursion (objtool bug!)
> >> drivers/char/ipmi/ipmi_ssif.o: warning: objtool: deliver_recv_msg()+0x0: infinite recursion (objtool bug!)
> >
> > Can you share the object file (or at least the .config and GCC version)?
> >
>
> gcc (SUSE Linux) 4.8.5
>
> config and .o file are attached.

Thanks, can you verify this fixes it?

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 92b6a2c21631..dae568fef2c1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -190,9 +190,13 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func,
continue;

if (recursion == 5) {
- WARN_FUNC("infinite recursion (objtool bug!)",
- dest->sec, dest->offset);
- return -1;
+ /*
+ * Infinite recursion: two functions
+ * have sibling calls to each other.
+ * This is a very rare case. It means
+ * they aren't dead ends.
+ */
+ return 0;
}

return __dead_end_function(file, dest_func,