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182 lines
4.6 KiB
182 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* RT-Mutexes: blocking mutual exclusion locks with PI support |
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* |
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* started by Ingo Molnar and Thomas Gleixner: |
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* |
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* Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <[email protected]> |
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* Copyright (C) 2006 Timesys Corp., Thomas Gleixner <[email protected]> |
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* |
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* This code is based on the rt.c implementation in the preempt-rt tree. |
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* Portions of said code are |
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* |
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* Copyright (C) 2004 LynuxWorks, Inc., Igor Manyilov, Bill Huey |
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* Copyright (C) 2006 Esben Nielsen |
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* Copyright (C) 2006 Kihon Technologies Inc., |
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* Steven Rostedt <[email protected]> |
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* |
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* See rt.c in preempt-rt for proper credits and further information |
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*/ |
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#include <linux/sched.h> |
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#include <linux/sched/rt.h> |
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#include <linux/sched/debug.h> |
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#include <linux/delay.h> |
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#include <linux/export.h> |
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#include <linux/spinlock.h> |
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#include <linux/kallsyms.h> |
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#include <linux/syscalls.h> |
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#include <linux/interrupt.h> |
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#include <linux/rbtree.h> |
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#include <linux/fs.h> |
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#include <linux/debug_locks.h> |
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#include "rtmutex_common.h" |
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static void printk_task(struct task_struct *p) |
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{ |
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if (p) |
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printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio); |
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else |
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printk("<none>"); |
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} |
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static void printk_lock(struct rt_mutex *lock, int print_owner) |
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{ |
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if (lock->name) |
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printk(" [%p] {%s}\n", |
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lock, lock->name); |
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else |
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printk(" [%p] {%s:%d}\n", |
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lock, lock->file, lock->line); |
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if (print_owner && rt_mutex_owner(lock)) { |
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printk(".. ->owner: %p\n", lock->owner); |
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printk(".. held by: "); |
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printk_task(rt_mutex_owner(lock)); |
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printk("\n"); |
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} |
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} |
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void rt_mutex_debug_task_free(struct task_struct *task) |
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{ |
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DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); |
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DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); |
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} |
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/* |
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* We fill out the fields in the waiter to store the information about |
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* the deadlock. We print when we return. act_waiter can be NULL in |
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* case of a remove waiter operation. |
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*/ |
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void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk, |
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struct rt_mutex_waiter *act_waiter, |
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struct rt_mutex *lock) |
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{ |
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struct task_struct *task; |
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if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter) |
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return; |
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task = rt_mutex_owner(act_waiter->lock); |
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if (task && task != current) { |
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act_waiter->deadlock_task_pid = get_pid(task_pid(task)); |
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act_waiter->deadlock_lock = lock; |
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} |
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} |
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void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter) |
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{ |
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struct task_struct *task; |
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if (!waiter->deadlock_lock || !debug_locks) |
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return; |
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rcu_read_lock(); |
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task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID); |
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if (!task) { |
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rcu_read_unlock(); |
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return; |
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} |
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if (!debug_locks_off()) { |
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rcu_read_unlock(); |
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return; |
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} |
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pr_warn("\n"); |
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pr_warn("============================================\n"); |
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pr_warn("WARNING: circular locking deadlock detected!\n"); |
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pr_warn("%s\n", print_tainted()); |
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pr_warn("--------------------------------------------\n"); |
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printk("%s/%d is deadlocking current task %s/%d\n\n", |
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task->comm, task_pid_nr(task), |
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current->comm, task_pid_nr(current)); |
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printk("\n1) %s/%d is trying to acquire this lock:\n", |
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current->comm, task_pid_nr(current)); |
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printk_lock(waiter->lock, 1); |
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printk("\n2) %s/%d is blocked on this lock:\n", |
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task->comm, task_pid_nr(task)); |
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printk_lock(waiter->deadlock_lock, 1); |
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debug_show_held_locks(current); |
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debug_show_held_locks(task); |
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printk("\n%s/%d's [blocked] stackdump:\n\n", |
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task->comm, task_pid_nr(task)); |
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show_stack(task, NULL, KERN_DEFAULT); |
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printk("\n%s/%d's [current] stackdump:\n\n", |
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current->comm, task_pid_nr(current)); |
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dump_stack(); |
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debug_show_all_locks(); |
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rcu_read_unlock(); |
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printk("[ turning off deadlock detection." |
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"Please report this trace. ]\n\n"); |
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} |
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void debug_rt_mutex_lock(struct rt_mutex *lock) |
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{ |
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} |
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void debug_rt_mutex_unlock(struct rt_mutex *lock) |
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{ |
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DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current); |
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} |
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void |
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debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner) |
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{ |
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} |
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void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock) |
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{ |
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DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock)); |
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} |
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void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) |
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{ |
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memset(waiter, 0x11, sizeof(*waiter)); |
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waiter->deadlock_task_pid = NULL; |
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} |
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void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) |
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{ |
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put_pid(waiter->deadlock_task_pid); |
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memset(waiter, 0x22, sizeof(*waiter)); |
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} |
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void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key) |
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{ |
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/* |
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* Make sure we are not reinitializing a held lock: |
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*/ |
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debug_check_no_locks_freed((void *)lock, sizeof(*lock)); |
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lock->name = name; |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC |
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lockdep_init_map(&lock->dep_map, name, key, 0); |
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#endif |
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} |
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