On Wed, Sep 30, 2026 at 5:08 AM Paul E. McKenney <[email protected]> wrote: > > On Mon, Sep 28, 2026 at 10:54:13AM +0800, KunWu Chan wrote: > > Thanks, Arnd. > > > > Tested on top of 1eccf02fb8d5 with CONFIG_PREEMPT_RCU=y: > > > > CONFIG_RT_MUTEXES=y: build passes > > CONFIG_RT_MUTEXES=n: fails without this patch, passes with it > > > > The failure is in tree_stall.h, where rt_mutex_owner() is used > > before tree_plugin.h includes rtmutex_common.h. This matches the > > reported failure, and the added include fixes it. > > > > Reviewed-by: Kunwu Chan <[email protected]> > > Tested-by: Kunwu Chan <[email protected]> > > Bradley and Kunwu, are you OK with my applying your tags to the commit > that I am merging this into? > > 1eccf02fb8d5 ("rcu: Add running and boosted indications to RCU task stall > dump") > > Thanx, Paul >
Sure. Thanks, Paul. Kunwu > > Thanks, > > Kunwu > > > > On Fri, Sep 25, 2026 at 9:39 PM 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]> > > > --- > > > 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" > > > > > > > > > ////////////////////////////////////////////////////////////////////////////// > > > // > > > -- > > > 2.53.0 > > > > >
