In a previous patch series [1], we added an optional lockdep expression argument to list_for_each_entry_rcu() and the hlist equivalent. This also meant more than one optional argument can be passed to them with that error going unnoticed. To fix this, let us force a compiler error more than one optional argument is passed.
[1] https://lore.kernel.org/patchwork/project/lkml/list/?series=402150 Suggested-by: Paul McKenney <paul...@linux.vnet.ibm.com> Signed-off-by: Joel Fernandes (Google) <j...@joelfernandes.org> --- include/linux/rculist.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 1048160625bb..86659f6d72dc 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -44,14 +44,18 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) * Check during list traversal that we are within an RCU reader */ +#define check_arg_count_one(dummy) + #ifdef CONFIG_PROVE_RCU_LIST -#define __list_check_rcu(dummy, cond, ...) \ +#define __list_check_rcu(dummy, cond, extra...) \ ({ \ + check_arg_count_one(extra); \ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \ "RCU-list traversed in non-reader section!"); \ }) #else -#define __list_check_rcu(dummy, cond, ...) ({}) +#define __list_check_rcu(dummy, cond, extra...) \ + ({ check_arg_count_one(extra); }) #endif /* -- 2.22.0.510.g264f2c817a-goog
