Hi Mao, Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on tip/locking/core] [also build test WARNING on v4.18-rc8 next-20180807] [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/Mao-Wenan/rtmutex-Drop-pointless-static-qualifier-in-rt_mutex_adjust_prio_chain/20180808-013010 config: x86_64-randconfig-x010-201831 (attached as .config) compiler: gcc-7 (Debian 7.3.0-16) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): kernel/locking/rtmutex.c: In function 'rt_mutex_adjust_prio_chain': >> kernel/locking/rtmutex.c:481:6: warning: 'prev_max' may be used >> uninitialized in this function [-Wmaybe-uninitialized] if (prev_max != max_lock_depth) { ^ vim +/prev_max +481 kernel/locking/rtmutex.c 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 384 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 385 /* 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 386 * Adjust the priority chain. Also used for deadlock detection. 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 387 * Decreases task's usage by one - may thus free the task. 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 388 * 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 389 * @task: the task owning the mutex (owner) for which a chain walk is 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 390 * probably needed e6beaa363 kernel/locking/rtmutex.c Tom(JeHyeon Yeon 2015-03-18 391) * @chwalk: do we have to carry out deadlock detection? 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 392 * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 393 * things for a task that has just got its priority adjusted, and 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 394 * is waiting on a mutex) 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 395 * @next_lock: the mutex on which the owner of @orig_lock was blocked before 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 396 * we dropped its pi_lock. Is never dereferenced, only used for 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 397 * comparison to detect lock chain changes. 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 398 * @orig_waiter: rt_mutex_waiter struct for the task that has just donated 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 399 * its priority to the mutex owner (can be NULL in the case 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 400 * depicted above or if the top waiter is gone away and we are 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 401 * actually deboosting the owner) 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 402 * @top_task: the current top waiter 0c1061733 kernel/rtmutex.c Juri Lelli 2013-05-15 403 * 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 404 * Returns 0 or -EDEADLK. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 405 * 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 406 * Chain walk basics and protection scope 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 407 * 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 408 * [R] refcount on task 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 409 * [P] task->pi_lock held 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 410 * [L] rtmutex->wait_lock held 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 411 * 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 412 * Step Description Protected by 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 413 * function arguments: 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 414 * @task [R] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 415 * @orig_lock if != NULL @top_task is blocked on it 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 416 * @next_lock Unprotected. Cannot be 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 417 * dereferenced. Only used for 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 418 * comparison. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 419 * @orig_waiter if != NULL @top_task is blocked on it 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 420 * @top_task current, or in case of proxy 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 421 * locking protected by calling 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 422 * code 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 423 * again: 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 424 * loop_sanity_check(); 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 425 * retry: 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 426 * [1] lock(task->pi_lock); [R] acquire [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 427 * [2] waiter = task->pi_blocked_on; [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 428 * [3] check_exit_conditions_1(); [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 429 * [4] lock = waiter->lock; [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 430 * [5] if (!try_lock(lock->wait_lock)) { [P] try to acquire [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 431 * unlock(task->pi_lock); release [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 432 * goto retry; 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 433 * } 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 434 * [6] check_exit_conditions_2(); [P] + [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 435 * [7] requeue_lock_waiter(lock, waiter); [P] + [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 436 * [8] unlock(task->pi_lock); release [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 437 * put_task_struct(task); release [R] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 438 * [9] check_exit_conditions_3(); [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 439 * [10] task = owner(lock); [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 440 * get_task_struct(task); [L] acquire [R] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 441 * lock(task->pi_lock); [L] acquire [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 442 * [11] requeue_pi_waiter(tsk, waiters(lock));[P] + [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 443 * [12] check_exit_conditions_4(); [P] + [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 444 * [13] unlock(task->pi_lock); release [P] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 445 * unlock(lock->wait_lock); release [L] 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 446 * goto again; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 447 */ bd197234b kernel/rtmutex.c Thomas Gleixner 2007-06-17 448 static int rt_mutex_adjust_prio_chain(struct task_struct *task, 8930ed80f kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 449 enum rtmutex_chainwalk chwalk, 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 450 struct rt_mutex *orig_lock, 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 451 struct rt_mutex *next_lock, 95e02ca9b kernel/rtmutex.c Thomas Gleixner 2006-06-27 452 struct rt_mutex_waiter *orig_waiter, 9a11b49a8 kernel/rtmutex.c Ingo Molnar 2006-07-03 453 struct task_struct *top_task) 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 454 { 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 455 struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 456 struct rt_mutex_waiter *prerequeue_top_waiter; 8930ed80f kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 457 int ret = 0, depth = 0; a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 458 struct rt_mutex *lock; 8930ed80f kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 459 bool detect_deadlock; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 460 bool requeue = true; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 461 8930ed80f kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 462 detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter, chwalk); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 463 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 464 /* 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 465 * The (de)boosting is a step by step approach with a lot of 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 466 * pitfalls. We want this to be preemptible and we want hold a 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 467 * maximum of two locks per step. So we have to check 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 468 * carefully whether things change under us. 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 469 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 470 again: 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 471 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 472 * We limit the lock chain length for each invocation. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 473 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 474 if (++depth > max_lock_depth) { 3ac304ec5 kernel/locking/rtmutex.c Mao Wenan 2018-08-07 475 int prev_max; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 476 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 477 /* 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 478 * Print this only once. If the admin changes the limit, 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 479 * print a new message when reaching the limit again. 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 480 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 @481 if (prev_max != max_lock_depth) { 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 482 prev_max = max_lock_depth; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 483 printk(KERN_WARNING "Maximum lock depth %d reached " 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 484 "task: %s (%d)\n", max_lock_depth, ba25f9dcc kernel/rtmutex.c Pavel Emelyanov 2007-10-18 485 top_task->comm, task_pid_nr(top_task)); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 486 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 487 put_task_struct(task); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 488 3d5c9340d kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 489 return -EDEADLK; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 490 } 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 491 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 492 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 493 * We are fully preemptible here and only hold the refcount on 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 494 * @task. So everything can have changed under us since the 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 495 * caller or our own code below (goto retry/again) dropped all 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 496 * locks. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 497 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 498 retry: 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 499 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 500 * [1] Task cannot go away as we did a get_task() before ! 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 501 */ b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 502 raw_spin_lock_irq(&task->pi_lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 503 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 504 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 505 * [2] Get the waiter on which @task is blocked on. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 506 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 507 waiter = task->pi_blocked_on; 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 508 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 509 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 510 * [3] check_exit_conditions_1() protected by task->pi_lock. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 511 */ 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 512 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 513 /* 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 514 * Check whether the end of the boosting chain has been 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 515 * reached or the state of the chain has changed while we 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 516 * dropped the locks. 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 517 */ 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 518 if (!waiter) 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 519 goto out_unlock_pi; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 520 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 521 /* 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 522 * Check the orig_waiter state. After we dropped the locks, 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 523 * the previous owner of the lock might have released the lock. 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 524 */ 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 525 if (orig_waiter && !rt_mutex_owner(orig_lock)) 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 526 goto out_unlock_pi; 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 527 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 528 /* 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 529 * We dropped all locks after taking a refcount on @task, so 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 530 * the task might have moved on in the lock chain or even left 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 531 * the chain completely and blocks now on an unrelated lock or 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 532 * on @orig_lock. 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 533 * 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 534 * We stored the lock on which @task was blocked in @next_lock, 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 535 * so we can detect the chain change. 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 536 */ 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 537 if (next_lock != waiter->lock) 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 538 goto out_unlock_pi; 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 539 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 540 /* 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 541 * Drop out, when the task has no waiters. Note, 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 542 * top_waiter can be NULL, when we are in the deboosting 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 543 * mode! 1a539a872 kernel/rtmutex.c Thomas Gleixner 2007-06-08 544 */ 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 545 if (top_waiter) { 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 546 if (!task_has_pi_waiters(task)) 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 547 goto out_unlock_pi; 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 548 /* 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 549 * If deadlock detection is off, we stop here if we 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 550 * are not the top pi waiter of the task. If deadlock 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 551 * detection is enabled we continue, but stop the 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 552 * requeueing in the chain walk. 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 553 */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 554 if (top_waiter != task_top_pi_waiter(task)) { 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 555 if (!detect_deadlock) 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 556 goto out_unlock_pi; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 557 else 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 558 requeue = false; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 559 } 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 560 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 561 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 562 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 563 * If the waiter priority is the same as the task priority 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 564 * then there is no further priority adjustment necessary. If 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 565 * deadlock detection is off, we stop the chain walk. If its 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 566 * enabled we continue, but stop the requeueing in the chain 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 567 * walk. 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 568 */ 19830e552 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 569 if (rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 570 if (!detect_deadlock) 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 571 goto out_unlock_pi; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 572 else 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 573 requeue = false; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 574 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 575 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 576 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 577 * [4] Get the next lock 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 578 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 579 lock = waiter->lock; 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 580 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 581 * [5] We need to trylock here as we are holding task->pi_lock, 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 582 * which is the reverse lock order versus the other rtmutex 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 583 * operations. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 584 */ d209d74d5 kernel/rtmutex.c Thomas Gleixner 2009-11-17 585 if (!raw_spin_trylock(&lock->wait_lock)) { b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 586 raw_spin_unlock_irq(&task->pi_lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 587 cpu_relax(); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 588 goto retry; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 589 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 590 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 591 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 592 * [6] check_exit_conditions_2() protected by task->pi_lock and 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 593 * lock->wait_lock. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 594 * 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 595 * Deadlock detection. If the lock is the same as the original 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 596 * lock which caused us to walk the lock chain or if the 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 597 * current lock is owned by the task which initiated the chain 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 598 * walk, we detected a deadlock. 397335f00 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 599 */ 95e02ca9b kernel/rtmutex.c Thomas Gleixner 2006-06-27 600 if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { 8930ed80f kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 601 debug_rt_mutex_deadlock(chwalk, orig_waiter, lock); d209d74d5 kernel/rtmutex.c Thomas Gleixner 2009-11-17 602 raw_spin_unlock(&lock->wait_lock); 3d5c9340d kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 603 ret = -EDEADLK; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 604 goto out_unlock_pi; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 605 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 606 a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 607 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 608 * If we just follow the lock chain for deadlock detection, no 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 609 * need to do all the requeue operations. To avoid a truckload 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 610 * of conditionals around the various places below, just do the 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 611 * minimum chain walk checks. 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 612 */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 613 if (!requeue) { 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 614 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 615 * No requeue[7] here. Just release @task [8] 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 616 */ b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 617 raw_spin_unlock(&task->pi_lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 618 put_task_struct(task); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 619 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 620 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 621 * [9] check_exit_conditions_3 protected by lock->wait_lock. 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 622 * If there is no owner of the lock, end of chain. 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 623 */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 624 if (!rt_mutex_owner(lock)) { b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 625 raw_spin_unlock_irq(&lock->wait_lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 626 return 0; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 627 } 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 628 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 629 /* [10] Grab the next task, i.e. owner of @lock */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 630 task = rt_mutex_owner(lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 631 get_task_struct(task); b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 632 raw_spin_lock(&task->pi_lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 633 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 634 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 635 * No requeue [11] here. We just do deadlock detection. 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 636 * 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 637 * [12] Store whether owner is blocked 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 638 * itself. Decision is made after dropping the locks 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 639 */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 640 next_lock = task_blocked_on_lock(task); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 641 /* 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 642 * Get the top waiter for the next iteration 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 643 */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 644 top_waiter = rt_mutex_top_waiter(lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 645 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 646 /* [13] Drop locks */ b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 647 raw_spin_unlock(&task->pi_lock); b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 648 raw_spin_unlock_irq(&lock->wait_lock); 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 649 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 650 /* If owner is not blocked, end of chain. */ 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 651 if (!next_lock) 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 652 goto out_put_task; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 653 goto again; 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 654 } 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 655 67792e2ca kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 656 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 657 * Store the current top waiter before doing the requeue a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 658 * operation on @lock. We need it for the boost/deboost a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 659 * decision below. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 660 */ a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 661 prerequeue_top_waiter = rt_mutex_top_waiter(lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 662 9f40a51a3 kernel/locking/rtmutex.c Davidlohr Bueso 2015-05-19 663 /* [7] Requeue the waiter in the lock waiter tree. */ fb00aca47 kernel/locking/rtmutex.c Peter Zijlstra 2013-11-07 664 rt_mutex_dequeue(lock, waiter); e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 665 e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 666 /* e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 667 * Update the waiter prio fields now that we're dequeued. e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 668 * e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 669 * These values can have changed through either: e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 670 * e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 671 * sys_sched_set_scheduler() / sys_sched_setattr() e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 672 * e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 673 * or e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 674 * e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 675 * DL CBS enforcement advancing the effective deadline. e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 676 * e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 677 * Even though pi_waiters also uses these fields, and that tree is only e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 678 * updated in [11], we can do this here, since we hold [L], which e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 679 * serializes all pi_waiters access and rb_erase() does not care about e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 680 * the values of the node being removed. e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 681 */ 2d3d891d3 kernel/locking/rtmutex.c Dario Faggioli 2013-11-07 682 waiter->prio = task->prio; e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 683 waiter->deadline = task->dl.deadline; e0aad5b44 kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 684 fb00aca47 kernel/locking/rtmutex.c Peter Zijlstra 2013-11-07 685 rt_mutex_enqueue(lock, waiter); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 686 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 687 /* [8] Release the task */ b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 688 raw_spin_unlock(&task->pi_lock); 2ffa5a5cd kernel/locking/rtmutex.c Thomas Gleixner 2014-06-07 689 put_task_struct(task); 2ffa5a5cd kernel/locking/rtmutex.c Thomas Gleixner 2014-06-07 690 a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 691 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 692 * [9] check_exit_conditions_3 protected by lock->wait_lock. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 693 * a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 694 * We must abort the chain walk if there is no lock owner even a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 695 * in the dead lock detection case, as we have nothing to a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 696 * follow here. This is the end of the chain we are walking. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 697 */ 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 698 if (!rt_mutex_owner(lock)) { 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 699 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 700 * If the requeue [7] above changed the top waiter, 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 701 * then we need to wake the new top waiter up to try 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 702 * to get the lock. 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 703 */ a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 704 if (prerequeue_top_waiter != rt_mutex_top_waiter(lock)) 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 705 wake_up_process(rt_mutex_top_waiter(lock)->task); b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 706 raw_spin_unlock_irq(&lock->wait_lock); 2ffa5a5cd kernel/locking/rtmutex.c Thomas Gleixner 2014-06-07 707 return 0; 8161239a8 kernel/rtmutex.c Lai Jiangshan 2011-01-14 708 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 709 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 710 /* [10] Grab the next task, i.e. the owner of @lock */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 711 task = rt_mutex_owner(lock); db630637b kernel/rtmutex.c Steven Rostedt 2006-09-29 712 get_task_struct(task); b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 713 raw_spin_lock(&task->pi_lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 714 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 715 /* [11] requeue the pi waiters if necessary */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 716 if (waiter == rt_mutex_top_waiter(lock)) { a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 717 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 718 * The waiter became the new top (highest priority) a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 719 * waiter on the lock. Replace the previous top waiter 9f40a51a3 kernel/locking/rtmutex.c Davidlohr Bueso 2015-05-19 720 * in the owner tasks pi waiters tree with this waiter a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 721 * and adjust the priority of the owner. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 722 */ a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 723 rt_mutex_dequeue_pi(task, prerequeue_top_waiter); fb00aca47 kernel/locking/rtmutex.c Peter Zijlstra 2013-11-07 724 rt_mutex_enqueue_pi(task, waiter); acd58620e kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 725 rt_mutex_adjust_prio(task); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 726 a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 727 } else if (prerequeue_top_waiter == waiter) { a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 728 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 729 * The waiter was the top waiter on the lock, but is a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 730 * no longer the top prority waiter. Replace waiter in 9f40a51a3 kernel/locking/rtmutex.c Davidlohr Bueso 2015-05-19 731 * the owner tasks pi waiters tree with the new top a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 732 * (highest priority) waiter and adjust the priority a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 733 * of the owner. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 734 * The new top waiter is stored in @waiter so that a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 735 * @waiter == @top_waiter evaluates to true below and a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 736 * we continue to deboost the rest of the chain. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 737 */ fb00aca47 kernel/locking/rtmutex.c Peter Zijlstra 2013-11-07 738 rt_mutex_dequeue_pi(task, waiter); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 739 waiter = rt_mutex_top_waiter(lock); fb00aca47 kernel/locking/rtmutex.c Peter Zijlstra 2013-11-07 740 rt_mutex_enqueue_pi(task, waiter); acd58620e kernel/locking/rtmutex.c Peter Zijlstra 2017-03-23 741 rt_mutex_adjust_prio(task); a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 742 } else { a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 743 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 744 * Nothing changed. No need to do any priority a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 745 * adjustment. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 746 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 747 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 748 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 749 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 750 * [12] check_exit_conditions_4() protected by task->pi_lock 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 751 * and lock->wait_lock. The actual decisions are made after we 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 752 * dropped the locks. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 753 * 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 754 * Check whether the task which owns the current lock is pi 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 755 * blocked itself. If yes we store a pointer to the lock for 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 756 * the lock chain change detection above. After we dropped 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 757 * task->pi_lock next_lock cannot be dereferenced anymore. 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 758 */ 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 759 next_lock = task_blocked_on_lock(task); a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 760 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 761 * Store the top waiter of @lock for the end of chain walk a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 762 * decision below. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 763 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 764 top_waiter = rt_mutex_top_waiter(lock); 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 765 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 766 /* [13] Drop the locks */ b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 767 raw_spin_unlock(&task->pi_lock); b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 768 raw_spin_unlock_irq(&lock->wait_lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 769 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 770 /* 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 771 * Make the actual exit decisions [12], based on the stored 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 772 * values. 3eb65aead kernel/locking/rtmutex.c Thomas Gleixner 2014-06-09 773 * 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 774 * We reached the end of the lock chain. Stop right here. No 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 775 * point to go back just to figure that out. 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 776 */ 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 777 if (!next_lock) 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 778 goto out_put_task; 820849843 kernel/locking/rtmutex.c Thomas Gleixner 2014-06-05 779 a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 780 /* a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 781 * If the current waiter is not the top waiter on the lock, a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 782 * then we can stop the chain walk here if we are not in full a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 783 * deadlock detection mode. a57594a13 kernel/locking/rtmutex.c Thomas Gleixner 2014-05-22 784 */ 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 785 if (!detect_deadlock && waiter != top_waiter) 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 786 goto out_put_task; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 787 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 788 goto again; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 789 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 790 out_unlock_pi: b4abf9104 kernel/locking/rtmutex.c Thomas Gleixner 2016-01-13 791 raw_spin_unlock_irq(&task->pi_lock); 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 792 out_put_task: 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 793 put_task_struct(task); 36c8b5868 kernel/rtmutex.c Ingo Molnar 2006-07-03 794 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 795 return ret; 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 796 } 23f78d4a0 kernel/rtmutex.c Ingo Molnar 2006-06-27 797 :::::: The code at line 481 was first introduced by commit :::::: 23f78d4a03c53cbd75d87a795378ea540aa08c86 [PATCH] pi-futex: rt mutex core :::::: TO: Ingo Molnar <[email protected]> :::::: CC: Linus Torvalds <[email protected]> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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