Re: [paulmckrcu:dev 47/49] ERROR: modpost: "rcutorture_format_gp_seqs" [kernel/rcu/rcutorture.ko] undefined!

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Dec 10, 2024 at 10:47:22AM -0800, Paul E. McKenney wrote:
> On Wed, Dec 04, 2024 at 12:04:15PM +0800, kernel test robot wrote:
> > tree:   https://github.com/paulmckrcu/linux dev
> > head:   48ca997e8632db65609dcc6a715207a1b6dded57
> > commit: 13e3224fa73ec6c7dfeda04b2741c95787196588 [47/49] rcutorture: Include grace-period sequence numbers in failure/close-call
> > config: arm-randconfig-001-20241203 (https://download.01.org/0day-ci/archive/20241204/202412041204.ys3dSglL-lkp@intel.com/config)
> > compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 592c0fe55f6d9a811028b5f3507be91458ab2713)
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241204/202412041204.ys3dSglL-lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202412041204.ys3dSglL-lkp@intel.com/
> > 
> > All errors (new ones prefixed by >>, old ones prefixed by <<):
> > 
> > ERROR: modpost: "rcutorture_gather_gp_seqs" [kernel/rcu/rcutorture.ko] undefined!
> > >> ERROR: modpost: "rcutorture_format_gp_seqs" [kernel/rcu/rcutorture.ko] undefined!
> 
> This commit has EXPORT_SYMBOL_GPL() for both the Tree and Tiny definitions
> of both of these functions.  What am I missing here?

This configuration has CONFIG_RCU_TINY=y and CONFIG_RCU_TORTURE_TEST=m,
so the definition and export do not work correctly because the define is
CONFIG_RCU_TORTURE_TEST_MODULE in that case. I think you should be using
IS_ENABLED(), which will handle =y and =m. This resolves the error for
me.

Cheers,
Nathan

diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index f068bd9dc037..773944257e79 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -257,7 +257,7 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
 EXPORT_SYMBOL_GPL(kvfree_call_rcu);
 #endif
 
-#ifdef CONFIG_RCU_TORTURE_TEST
+#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST)
 unsigned long rcutorture_gather_gp_seqs(void)
 {
 	return READ_ONCE(rcu_ctrlblk.gp_seq) & 0xff;