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* [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
@ 2023-03-19  7:05 kernel test robot
  2023-03-19 17:26 ` Paul E. McKenney
  2023-03-20  0:33 ` Paul E. McKenney
  0 siblings, 2 replies; 7+ messages in thread
From: kernel test robot @ 2023-03-19  7:05 UTC (permalink / raw)
  To: Paul E. McKenney; +Cc: oe-kbuild-all, linux-kernel

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);
         | ^~~~~~~~~~~~~~~~~~


vim +/tasks_rcu_exit_srcu +140 kernel/rcu/tasks.h

07e105158d97b4 Paul E. McKenney 2020-03-02  138  
eacd6f04a13331 Paul E. McKenney 2020-03-02  139  /* Track exiting tasks in order to allow them to be waited for. */
eacd6f04a13331 Paul E. McKenney 2020-03-02 @140  DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu);
eacd6f04a13331 Paul E. McKenney 2020-03-02  141  

:::::: The code at line 140 was first introduced by commit
:::::: eacd6f04a1333187dd3e96e5635c0edce0a2e354 rcu-tasks: Move Tasks RCU to its own file

:::::: TO: Paul E. McKenney <paulmck@kernel.org>
:::::: CC: Paul E. McKenney <paulmck@kernel.org>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-19  7:05 [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used kernel test robot
@ 2023-03-19 17:26 ` Paul E. McKenney
  2023-03-20  0:33 ` Paul E. McKenney
  1 sibling, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2023-03-19 17:26 UTC (permalink / raw)
  To: kernel test robot; +Cc: oe-kbuild-all, linux-kernel

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);
>          | ^~~~~~~~~~~~~~~~~~

It is true that if you build a kernel with CONFIG_TASKS_RCU_GENERIC=y and
CONFIG_TASKS_RCU=n, you will get this warning.  I am at a loss as to why
this commit would have changed that, but in any case it does need a fix.

Thank you for catching it!

							Thanx, Paul

> vim +/tasks_rcu_exit_srcu +140 kernel/rcu/tasks.h
> 
> 07e105158d97b4 Paul E. McKenney 2020-03-02  138  
> eacd6f04a13331 Paul E. McKenney 2020-03-02  139  /* Track exiting tasks in order to allow them to be waited for. */
> eacd6f04a13331 Paul E. McKenney 2020-03-02 @140  DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu);
> eacd6f04a13331 Paul E. McKenney 2020-03-02  141  
> 
> :::::: The code at line 140 was first introduced by commit
> :::::: eacd6f04a1333187dd3e96e5635c0edce0a2e354 rcu-tasks: Move Tasks RCU to its own file
> 
> :::::: TO: Paul E. McKenney <paulmck@kernel.org>
> :::::: CC: Paul E. McKenney <paulmck@kernel.org>
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-19  7:05 [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used kernel test robot
  2023-03-19 17:26 ` Paul E. McKenney
@ 2023-03-20  0:33 ` Paul E. McKenney
  2023-03-21  2:49   ` Liu, Yujie
  1 sibling, 1 reply; 7+ messages in thread
From: Paul E. McKenney @ 2023-03-20  0:33 UTC (permalink / raw)
  To: kernel test robot; +Cc: oe-kbuild-all, linux-kernel

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?

							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);

^ permalink raw reply related	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-20  0:33 ` Paul E. McKenney
@ 2023-03-21  2:49   ` Liu, Yujie
  2023-03-21  4:18     ` Paul E. McKenney
  0 siblings, 1 reply; 7+ messages in thread
From: Liu, Yujie @ 2023-03-21  2:49 UTC (permalink / raw)
  To: paulmck, lkp; +Cc: linux-kernel, oe-kbuild-all

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);
> 


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-21  2:49   ` Liu, Yujie
@ 2023-03-21  4:18     ` Paul E. McKenney
  2023-03-21  6:16       ` Liu, Yujie
  0 siblings, 1 reply; 7+ messages in thread
From: Paul E. McKenney @ 2023-03-21  4:18 UTC (permalink / raw)
  To: Liu, Yujie; +Cc: lkp, linux-kernel, oe-kbuild-all

On Tue, Mar 21, 2023 at 02:49:08AM +0000, Liu, Yujie wrote:
> 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.

Thank you!  May I apply your Tested-by?

							Thanx, Paul

> --
> 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);
> > 
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-21  4:18     ` Paul E. McKenney
@ 2023-03-21  6:16       ` Liu, Yujie
  2023-03-21 15:52         ` Paul E. McKenney
  0 siblings, 1 reply; 7+ messages in thread
From: Liu, Yujie @ 2023-03-21  6:16 UTC (permalink / raw)
  To: paulmck; +Cc: linux-kernel, lkp, oe-kbuild-all

On Mon, 2023-03-20 at 21:18 -0700, Paul E. McKenney wrote:
> On Tue, Mar 21, 2023 at 02:49:08AM +0000, Liu, Yujie wrote:
> > 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.
> 
> Thank you!  May I apply your Tested-by?

Sure, with pleasure.

Tested-by: Yujie Liu <yujie.liu@intel.com>

Thanks.

>                                                         Thanx, Paul
> 
> > --
> > 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);
> > > 
> > 
> 


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used
  2023-03-21  6:16       ` Liu, Yujie
@ 2023-03-21 15:52         ` Paul E. McKenney
  0 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2023-03-21 15:52 UTC (permalink / raw)
  To: Liu, Yujie; +Cc: linux-kernel, lkp, oe-kbuild-all

On Tue, Mar 21, 2023 at 06:16:04AM +0000, Liu, Yujie wrote:
> On Mon, 2023-03-20 at 21:18 -0700, Paul E. McKenney wrote:
> > On Tue, Mar 21, 2023 at 02:49:08AM +0000, Liu, Yujie wrote:
> > > 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.
> > 
> > Thank you!  May I apply your Tested-by?
> 
> Sure, with pleasure.
> 
> Tested-by: Yujie Liu <yujie.liu@intel.com>

Thank you, and I will apply on my next rebase.

							Thanx, Paul

> Thanks.
> 
> >                                                         Thanx, Paul
> > 
> > > --
> > > 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);
> > > > 
> > > 
> > 
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2023-03-21 15:52 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-19  7:05 [paulmck-rcu:dev.2023.03.17a 33/38] kernel/rcu/tasks.h:140:20: warning: 'tasks_rcu_exit_srcu' defined but not used kernel test robot
2023-03-19 17:26 ` Paul E. McKenney
2023-03-20  0:33 ` Paul E. McKenney
2023-03-21  2:49   ` Liu, Yujie
2023-03-21  4:18     ` Paul E. McKenney
2023-03-21  6:16       ` Liu, Yujie
2023-03-21 15:52         ` Paul E. McKenney

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