Messages in this thread | | | From | "Liu, Yujie" <> | Subject | Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used | Date | Tue, 21 Mar 2023 02:49:08 +0000 |
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Hi Paul,
On Sun, 2023-03-19 at 17:33 -0700, Paul E. McKenney wrote: > On Sun, Mar 19, 2023 at 03:05:43PM +0800, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2023.03.17a > > head: 19d218a4b125a4dce12eb88097a9c55f7126ce8c > > commit: 61eea4556e8cf92d4c9b483110a679d2652aa451 [33/38] srcu: Move work-scheduling fields from srcu_struct to srcu_usage > > config: x86_64-kexec (https://download.01.org/0day-ci/archive/20230319/202303191536.XzMSyzTl-lkp@intel.com/config) > > compiler: gcc-11 (Debian 11.3.0-8) 11.3.0 > > reproduce (this is a W=1 build): > > # https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?id=61eea4556e8cf92d4c9b483110a679d2652aa451 > > git remote add paulmck-rcu https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git > > git fetch --no-tags paulmck-rcu dev.2023.03.17a > > git checkout 61eea4556e8cf92d4c9b483110a679d2652aa451 > > # save the config file > > mkdir build_dir && cp config build_dir/.config > > make W=1 O=build_dir ARCH=x86_64 olddefconfig > > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash kernel/ > > > > If you fix the issue, kindly add following tag where applicable > > > Reported-by: kernel test robot <lkp@intel.com> > > > Link: https://lore.kernel.org/oe-kbuild-all/202303191536.XzMSyzTl-lkp@intel.com/ > > > > All warnings (new ones prefixed by >>): > > > > In file included from include/linux/srcu.h:49, > > from include/linux/notifier.h:16, > > from arch/x86/include/asm/uprobes.h:13, > > from include/linux/uprobes.h:49, > > from include/linux/mm_types.h:16, > > from include/linux/sched/signal.h:13, > > from kernel/rcu/update.c:26: > > > > kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used [-Wunused-variable] > > 140 | DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); > > | ^~~~~~~~~~~~~~~~~~~ > > include/linux/srcutree.h:184:38: note: in definition of macro '__DEFINE_SRCU' > > 184 | is_static struct srcu_struct name = \ > > | ^~~~ > > kernel/rcu/tasks.h:140:1: note: in expansion of macro 'DEFINE_STATIC_SRCU' > > 140 | DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); > > | ^~~~~~~~~~~~~~~~~~ > > Good catch, thank you! > > Does the patch shown below fix this?
We've tested the patch and the build warning is fixed by it. Thanks.
-- Best Regards, Yujie
> Thanx, Paul > > ------------------------------------------------------------------------ > > commit a9b8406e51603238941dbc6fa1437f8915254ebb > Author: Paul E. McKenney <paulmck@kernel.org> > Date: Sun Mar 19 17:29:20 2023 -0700 > > rcu-tasks: Fix warning for unused tasks_rcu_exit_srcu > > The tasks_rcu_exit_srcu variable is used only by kernels built > with CONFIG_TASKS_RCU=y, but is defined for all kernesl with > CONFIG_TASKS_RCU_GENERIC=y. Therefore, in kernels built with > CONFIG_TASKS_RCU_GENERIC=y but CONFIG_TASKS_RCU=n, this gives > a "defined but not used" warning. > > This commit therefore moves this variable under CONFIG_TASKS_RCU > > Link: https://lore.kernel.org/oe-kbuild-all/202303191536.XzMSyzTl-lkp@intel.com/ > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > index baf7ec178155..85a874d4166b 100644 > --- a/kernel/rcu/tasks.h > +++ b/kernel/rcu/tasks.h > @@ -136,10 +136,10 @@ static struct rcu_tasks rt_name = \ > .kname = #rt_name, \ > } > > +#ifdef CONFIG_TASKS_RCU > /* Track exiting tasks in order to allow them to be waited for. */ > DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); > > -#ifdef CONFIG_TASKS_RCU > /* Report delay in synchronize_srcu() completion in rcu_tasks_postscan(). */ > static void tasks_rcu_exit_srcu_stall(struct timer_list *unused); > static DEFINE_TIMER(tasks_rcu_exit_srcu_stall_timer, tasks_rcu_exit_srcu_stall); >
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