Messages in this thread | | | Date | Fri, 23 Dec 2016 03:27:15 +0800 | From | kbuild test robot <> | Subject | Re: [PATCH 1/2] sched: Introduce rcuwait machinery |
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Hi Davidlohr,
[auto build test ERROR on tip/auto-latest] [also build test ERROR on v4.9 next-20161222] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Davidlohr-Bueso/sched-Introduce-rcuwait/20161223-020109 config: i386-randconfig-s1-201651 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=i386
Note: the linux-review/Davidlohr-Bueso/sched-Introduce-rcuwait/20161223-020109 HEAD 9e9d238f94d5aa8e348e7e70585533fe0dbd373b builds fine. It only hurts bisectibility.
All error/warnings (new ones prefixed by >>):
>> kernel/exit.c:285:29: warning: 'struct rcuwait' declared inside parameter list will not be visible outside of this definition or declaration void rcuwait_trywake(struct rcuwait *w) ^~~~~~~ In file included from include/linux/srcu.h:33:0, from include/linux/notifier.h:15, from include/linux/memory_hotplug.h:6, from include/linux/mmzone.h:751, from include/linux/gfp.h:5, from include/linux/mm.h:9, from kernel/exit.c:7: kernel/exit.c: In function 'rcuwait_trywake': >> kernel/exit.c:308:26: error: dereferencing pointer to incomplete type 'struct rcuwait' task = rcu_dereference(w->task); ^ include/linux/rcupdate.h:606:10: note: in definition of macro '__rcu_dereference_check' typeof(*p) *________p1 = (typeof(*p) *__force)lockless_dereference(p); \ ^ include/linux/rcupdate.h:786:28: note: in expansion of macro 'rcu_dereference_check' #define rcu_dereference(p) rcu_dereference_check(p, 0) ^~~~~~~~~~~~~~~~~~~~~ >> kernel/exit.c:308:9: note: in expansion of macro 'rcu_dereference' task = rcu_dereference(w->task); ^~~~~~~~~~~~~~~
vim +308 kernel/exit.c
279 if (!sighand) 280 return NULL; 281 282 return task; 283 } 284 > 285 void rcuwait_trywake(struct rcuwait *w) 286 { 287 struct task_struct *task; 288 289 rcu_read_lock(); 290 291 /* 292 * Order condition vs @task, such that everything prior to the load 293 * of @task is visible. This is the condition as to why the user called 294 * rcuwait_trywake() in the first place. Pairs with set_current_state() 295 * barrier (A) in rcuwait_wait_event(). 296 * 297 * WAIT WAKE 298 * [S] tsk = current [S] cond = true 299 * MB (A) MB (B) 300 * [L] cond [L] tsk 301 */ 302 smp_rmb(); /* (B) */ 303 304 /* 305 * Avoid using task_rcu_dereference() magic as long as we are careful, 306 * see comment in rcuwait_wait_event() regarding ->exit_state. 307 */ > 308 task = rcu_dereference(w->task); 309 if (task) 310 wake_up_process(task); 311 rcu_read_unlock();
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