| lockdep.c (dd84cfff3cc3b79c9d616f85bd1178df135cbd1a) | lockdep.c (e67198cc05b8ecbb7b8e2d8ef9fb5c8d26821873) |
|---|---|
| 1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * kernel/lockdep.c 4 * 5 * Runtime locking correctness validator 6 * 7 * Started by Ingo Molnar: 8 * --- 5418 unchanged lines hidden (view full) --- 5427 struct held_lock *hlock = curr->held_locks + i; 5428 5429 if (match_held_lock(hlock, lock)) { 5430 /* 5431 * Grab 16bits of randomness; this is sufficient to not 5432 * be guessable and still allows some pin nesting in 5433 * our u32 pin_count. 5434 */ | 1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * kernel/lockdep.c 4 * 5 * Runtime locking correctness validator 6 * 7 * Started by Ingo Molnar: 8 * --- 5418 unchanged lines hidden (view full) --- 5427 struct held_lock *hlock = curr->held_locks + i; 5428 5429 if (match_held_lock(hlock, lock)) { 5430 /* 5431 * Grab 16bits of randomness; this is sufficient to not 5432 * be guessable and still allows some pin nesting in 5433 * our u32 pin_count. 5434 */ |
| 5435 cookie.val = 1 + (prandom_u32() >> 16); | 5435 cookie.val = 1 + (sched_clock() & 0xffff); |
| 5436 hlock->pin_count += cookie.val; 5437 return cookie; 5438 } 5439 } 5440 5441 WARN(1, "pinning an unheld lock\n"); 5442 return cookie; 5443} --- 1121 unchanged lines hidden (view full) --- 6565 !rcu_lockdep_current_cpu_online() 6566 ? "RCU used illegally from offline CPU!\n" 6567 : "", 6568 rcu_scheduler_active, dl, 6569 dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n"); 6570 6571 /* 6572 * If a CPU is in the RCU-free window in idle (ie: in the section | 5436 hlock->pin_count += cookie.val; 5437 return cookie; 5438 } 5439 } 5440 5441 WARN(1, "pinning an unheld lock\n"); 5442 return cookie; 5443} --- 1121 unchanged lines hidden (view full) --- 6565 !rcu_lockdep_current_cpu_online() 6566 ? "RCU used illegally from offline CPU!\n" 6567 : "", 6568 rcu_scheduler_active, dl, 6569 dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n"); 6570 6571 /* 6572 * If a CPU is in the RCU-free window in idle (ie: in the section |
| 6573 * between rcu_idle_enter() and rcu_idle_exit(), then RCU | 6573 * between ct_idle_enter() and ct_idle_exit(), then RCU |
| 6574 * considers that CPU to be in an "extended quiescent state", 6575 * which means that RCU will be completely ignoring that CPU. 6576 * Therefore, rcu_read_lock() and friends have absolutely no 6577 * effect on a CPU running in that state. In other words, even if 6578 * such an RCU-idle CPU has called rcu_read_lock(), RCU might well 6579 * delete data structures out from under it. RCU really has no 6580 * choice here: we need to keep an RCU-free window in idle where 6581 * the CPU may possibly enter into low power mode. This way we can --- 15 unchanged lines hidden --- | 6574 * considers that CPU to be in an "extended quiescent state", 6575 * which means that RCU will be completely ignoring that CPU. 6576 * Therefore, rcu_read_lock() and friends have absolutely no 6577 * effect on a CPU running in that state. In other words, even if 6578 * such an RCU-idle CPU has called rcu_read_lock(), RCU might well 6579 * delete data structures out from under it. RCU really has no 6580 * choice here: we need to keep an RCU-free window in idle where 6581 * the CPU may possibly enter into low power mode. This way we can --- 15 unchanged lines hidden --- |