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Subject[tomoyo-tomoyo-test1:master 1/1] include/linux/workqueue.h:610:2: warning: call to __warn_flushing_systemwide_wq declared with 'warning' attribute: Please avoid flushing system-wide workqueues.
tree:   git://git.osdn.net/gitroot/tomoyo/tomoyo-test1.git master
head: e449c388913ccd36641f7cc0c335029a7cc161f4
commit: e449c388913ccd36641f7cc0c335029a7cc161f4 [1/1] workqueue: Wrap flush_workqueue() using an inline function
config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220524/202205241340.Wrnl4CKV-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 10c9ecce9f6096e18222a331c5e7d085bd813f75)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git remote add tomoyo-tomoyo-test1 git://git.osdn.net/gitroot/tomoyo/tomoyo-test1.git
git fetch --no-tags tomoyo-tomoyo-test1 master
git checkout e449c388913ccd36641f7cc0c335029a7cc161f4
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/rtc/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

In file included from drivers/rtc/dev.c:13:
In file included from include/linux/compat.h:14:
In file included from include/linux/sem.h:5:
In file included from include/uapi/linux/sem.h:5:
In file included from include/linux/ipc.h:7:
In file included from include/linux/rhashtable-types.h:15:
>> include/linux/workqueue.h:610:2: warning: call to __warn_flushing_systemwide_wq declared with 'warning' attribute: Please avoid flushing system-wide workqueues. [-Wattribute-warning]
__warn_flushing_systemwide_wq();
^
1 warning generated.


vim +/warning +610 include/linux/workqueue.h

565
566 /*
567 * Detect attempt to flush system-wide workqueues at compile time when possible.
568 *
569 * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
570 * for reasons and steps for converting system-wide workqueues into local workqueues.
571 */
572 extern void __warn_flushing_systemwide_wq(void)
573 __compiletime_warning("Please avoid flushing system-wide workqueues.");
574
575 /**
576 * flush_scheduled_work - ensure that any scheduled work has run to completion.
577 *
578 * Forces execution of the kernel-global workqueue and blocks until its
579 * completion.
580 *
581 * It's very easy to get into trouble if you don't take great care.
582 * Either of the following situations will lead to deadlock:
583 *
584 * One of the work items currently on the workqueue needs to acquire
585 * a lock held by your code or its caller.
586 *
587 * Your code is running in the context of a work routine.
588 *
589 * They will be detected by lockdep when they occur, but the first might not
590 * occur very often. It depends on what work items are on the workqueue and
591 * what locks they need, which you have no control over.
592 *
593 * In most situations flushing the entire workqueue is overkill; you merely
594 * need to know that a particular work item isn't queued and isn't running.
595 * In such cases you should use cancel_delayed_work_sync() or
596 * cancel_work_sync() instead.
597 *
598 * Please stop calling this function! A conversion to stop flushing system-wide
599 * workqueues is in progress. This function will be removed after all in-tree
600 * users stopped calling this function.
601 */
602 static inline void flush_scheduled_work(void)
603 {
604 #if !defined(CONFIG_WERROR) && defined(CONFIG_PROVE_LOCKING)
605 /*
606 * Warn only if emitting warning message does not cause build failure
607 * and the developer wants warning about possibility of deadlock, for
608 * there are currently in-tree flush_scheduled_work() users.
609 */
> 610 __warn_flushing_systemwide_wq();
611 #endif
612 __flush_workqueue(system_wq);
613 }
614

--
0-DAY CI Kernel Test Service
https://01.org/lkp

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