da954044eb
In commit
f5694788ad ("rt_mutex: Add lockdep annotations")
rtmutex gained lockdep annotation for rt_mutex_lock() and and related
functions.
lockdep will see the locking order and may complain about a deadlock
before rtmutex' own mechanism gets a chance to detect it.
The rtmutex deadlock detector will only complain locks with the
RT_MUTEX_MIN_CHAINWALK and a waiter must be pending. That means it
works only for in-kernel locks because the futex interface always uses
RT_MUTEX_FULL_CHAINWALK.
The requirement for an active waiter limits the detector to actual
deadlocks and makes it possible to report potential deadlocks like
lockdep does.
It looks like lockdep is better suited for reporting deadlocks.
Remove rtmutex' debug print on deadlock detection.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
81 lines
2.0 KiB
C
81 lines
2.0 KiB
C
// 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 <mingo@redhat.com>
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* Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
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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 <rostedt@goodmis.org>
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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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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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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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}
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void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
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{
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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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#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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