On 25 September 2026 14:39:04 BST, Arnd Bergmann <[email protected]> wrote: >From: Arnd Bergmann <[email protected]> > >The added call to rt_mutex_owner() makes this fail to build in >some configurations: > >In file included from kernel/rcu/tree.c:5121: >kernel/rcu/tree_stall.h:333:8: error: call to undeclared function >'rt_mutex_owner'; ISO C99 and later do not support implicit function >declarations [-Wimplicit-function-declaration] > 333 | if (rt_mutex_owner(&rnp->boost_mtx.rtmutex) == > t) > | ^ >kernel/rcu/tree_stall.h:333:48: error: comparison between pointer and >integer ('int' and 'struct task_struct *') >[-Werror,-Wpointer-integer-compare] > 333 | if (rt_mutex_owner(&rnp->boost_mtx.rtmutex) == > t) > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ > ~ >In file included from kernel/rcu/tree.c:5124: >In file included from kernel/rcu/tree_plugin.h:14: >kernel/rcu/../locking/rtmutex_common.h:231:35: error: conflicting types >for 'rt_mutex_owner' > 231 | static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base > *lock) > | ^ >kernel/rcu/tree_stall.h:333:8: note: previous implicit declaration is here > 333 | if (rt_mutex_owner(&rnp->boost_mtx.rtmutex) == > t) > | ^ > >There are already a couple of inclusions of "../locking/rtmutex_common.h", >so assume this is safe to do here. > >Fixes: 1eccf02fb8d5 ("rcu: Add running and boosted indications to RCU task >stall dump") >Signed-off-by: Arnd Bergmann <[email protected]>
Looks "ok" Reviewed-by: Bradley Morgan <[email protected]> Perhaps Paul could suggest another alternative M >--- >I wonder if it would be better to either move the rt_mutex_owner() >definition into a global header like include/linux/rtmutex.h, or to >move the code out of tree_stall.h into a .c file, as this feels like a >layering violation. >--- > kernel/rcu/tree_stall.h | 1 + > 1 file changed, 1 insertion(+) > >diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h >index 5dded1e89197..803a56af3259 100644 >--- a/kernel/rcu/tree_stall.h >+++ b/kernel/rcu/tree_stall.h >@@ -12,6 +12,7 @@ > #include <linux/rcu_notifier.h> > #include <linux/smp.h> > #include <linux/rtmutex.h> >+#include "../locking/rtmutex_common.h" > > ////////////////////////////////////////////////////////////////////////////// > // > --- Thanks! "I'm not a very positive person" - Linus torvalds
