From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3DCDC433ED for ; Wed, 24 Mar 2021 07:23:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2C0E619FE for ; Wed, 24 Mar 2021 07:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235959AbhCXHXM (ORCPT ); Wed, 24 Mar 2021 03:23:12 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:38678 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233240AbhCXHWb (ORCPT ); Wed, 24 Mar 2021 03:22:31 -0400 Date: Wed, 24 Mar 2021 07:22:30 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1616570551; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lp4PI//EsZj8ntcv7ZK84zygL6tajpQwLsIDkiedZ5I=; b=rKhUuTqBcXdsO6BeRAKRPuP8C03YQSiyHr98nwI9PUoCZcvK7fgRUu2ei1vyai+xel4fVI FQbriAN2Eh+bbzYNIEGOQyT4DHy0d+vFHKUerMrNtbbNtdx4Qs1Zh3OA/rr1GqDBKM+65/ GOifng6LeVBHY5twRj4TOf3evqpPMD6KWq7K/0hUAkFfOmsxtrSV8KWlK9IKdJxe7GYXZQ CmHJ3iGtZeY5poA6CS4CNp205XrJZhP1XtgcRv7ojyKSAFW9sL0Np6MycvNXeLWnqv7CtQ DAiY00nCpZX9qMe/DobiUCTS768G7aaP5Gkxrg48kVGzWBo1DHNFQAwc41afew== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1616570551; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lp4PI//EsZj8ntcv7ZK84zygL6tajpQwLsIDkiedZ5I=; b=e/BOOddL/Ea/r6PO3NlUkVAt5wgbjh10lNCXBPCS47koq9p2SlJOFTlGv9GwoUiOz2TX40 ObwgTTkIwo/+7cBA== From: "tip-bot2 for Sebastian Andrzej Siewior" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] locking/rtmutex: Remove output from deadlock detector. Cc: Sebastian Andrzej Siewior , Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210323213707.773152524@linutronix.de> References: <20210323213707.773152524@linutronix.de> MIME-Version: 1.0 Message-ID: <161657055053.398.12246019843968811656.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/core branch of tip: Commit-ID: 5389aaaa737bf9b1d430143a15c37c6ee2d89a75 Gitweb: https://git.kernel.org/tip/5389aaaa737bf9b1d430143a15c37c6ee2d89a75 Author: Sebastian Andrzej Siewior AuthorDate: Tue, 23 Mar 2021 22:30:22 +01:00 Committer: Ingo Molnar CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00 locking/rtmutex: Remove output from deadlock detector. The rtmutex specific deadlock detector predates lockdep coverage of rtmutex and since the following commit it contains a lot of redundant functionality: f5694788ad8da ("rt_mutex: Add lockdep annotations") - lockdep will detect an potential deadlock before rtmutex-debug has a chance to do so - the dead lock debugging is restricted to rtmutexes which are not associated to futexes and have an active waiter, which is covered by lockdep already Remove the redundant functionality and move actual deadlock WARN() into the deadlock code path. The latter needs a seperate cleanup. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210323213707.773152524@linutronix.de --- include/linux/rtmutex.h | 7 +-- kernel/locking/rtmutex-debug.c | 97 +-------------------------------- kernel/locking/rtmutex-debug.h | 9 +--- kernel/locking/rtmutex.c | 7 +-- kernel/locking/rtmutex.h | 7 +-- kernel/locking/rtmutex_common.h | 4 +- 6 files changed, 1 insertion(+), 130 deletions(-) diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h index 48b334b..0725c4b 100644 --- a/include/linux/rtmutex.h +++ b/include/linux/rtmutex.h @@ -31,9 +31,6 @@ struct rt_mutex { raw_spinlock_t wait_lock; struct rb_root_cached waiters; struct task_struct *owner; -#ifdef CONFIG_DEBUG_RT_MUTEXES - const char *name; -#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif @@ -56,8 +53,6 @@ struct hrtimer_sleeper; #endif #ifdef CONFIG_DEBUG_RT_MUTEXES -# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ - , .name = #mutexname # define rt_mutex_init(mutex) \ do { \ @@ -67,7 +62,6 @@ do { \ extern void rt_mutex_debug_task_free(struct task_struct *tsk); #else -# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL, NULL) # define rt_mutex_debug_task_free(t) do { } while (0) #endif @@ -83,7 +77,6 @@ do { \ { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \ , .waiters = RB_ROOT_CACHED \ , .owner = NULL \ - __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)} #define DEFINE_RT_MUTEX(mutexname) \ diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c index 7e411b9..fb15010 100644 --- a/kernel/locking/rtmutex-debug.c +++ b/kernel/locking/rtmutex-debug.c @@ -32,105 +32,12 @@ #include "rtmutex_common.h" -static void printk_task(struct task_struct *p) -{ - if (p) - printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio); - else - printk(""); -} - -static void printk_lock(struct rt_mutex *lock, int print_owner) -{ - printk(" [%p] {%s}\n", lock, lock->name); - - if (print_owner && rt_mutex_owner(lock)) { - printk(".. ->owner: %p\n", lock->owner); - printk(".. held by: "); - printk_task(rt_mutex_owner(lock)); - printk("\n"); - } -} - void rt_mutex_debug_task_free(struct task_struct *task) { DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); } -/* - * We fill out the fields in the waiter to store the information about - * the deadlock. We print when we return. act_waiter can be NULL in - * case of a remove waiter operation. - */ -void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk, - struct rt_mutex_waiter *act_waiter, - struct rt_mutex *lock) -{ - struct task_struct *task; - - if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter) - return; - - task = rt_mutex_owner(act_waiter->lock); - if (task && task != current) { - act_waiter->deadlock_task_pid = get_pid(task_pid(task)); - act_waiter->deadlock_lock = lock; - } -} - -void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter) -{ - struct task_struct *task; - - if (!waiter->deadlock_lock || !debug_locks) - return; - - rcu_read_lock(); - task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID); - if (!task) { - rcu_read_unlock(); - return; - } - - if (!debug_locks_off()) { - rcu_read_unlock(); - return; - } - - pr_warn("\n"); - pr_warn("============================================\n"); - pr_warn("WARNING: circular locking deadlock detected!\n"); - pr_warn("%s\n", print_tainted()); - pr_warn("--------------------------------------------\n"); - printk("%s/%d is deadlocking current task %s/%d\n\n", - task->comm, task_pid_nr(task), - current->comm, task_pid_nr(current)); - - printk("\n1) %s/%d is trying to acquire this lock:\n", - current->comm, task_pid_nr(current)); - printk_lock(waiter->lock, 1); - - printk("\n2) %s/%d is blocked on this lock:\n", - task->comm, task_pid_nr(task)); - printk_lock(waiter->deadlock_lock, 1); - - debug_show_held_locks(current); - debug_show_held_locks(task); - - printk("\n%s/%d's [blocked] stackdump:\n\n", - task->comm, task_pid_nr(task)); - show_stack(task, NULL, KERN_DEFAULT); - printk("\n%s/%d's [current] stackdump:\n\n", - current->comm, task_pid_nr(current)); - dump_stack(); - debug_show_all_locks(); - rcu_read_unlock(); - - printk("[ turning off deadlock detection." - "Please report this trace. ]\n\n"); -} - void debug_rt_mutex_lock(struct rt_mutex *lock) { } @@ -153,12 +60,10 @@ void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock) void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) { memset(waiter, 0x11, sizeof(*waiter)); - waiter->deadlock_task_pid = NULL; } void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) { - put_pid(waiter->deadlock_task_pid); memset(waiter, 0x22, sizeof(*waiter)); } @@ -168,10 +73,8 @@ void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_cl * Make sure we are not reinitializing a held lock: */ debug_check_no_locks_freed((void *)lock, sizeof(*lock)); - lock->name = name; #ifdef CONFIG_DEBUG_LOCK_ALLOC lockdep_init_map(&lock->dep_map, name, key, 0); #endif } - diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h index 772c9b0..659e93e 100644 --- a/kernel/locking/rtmutex-debug.h +++ b/kernel/locking/rtmutex-debug.h @@ -18,18 +18,9 @@ extern void debug_rt_mutex_unlock(struct rt_mutex *lock); extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner); extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock); -extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk, - struct rt_mutex_waiter *waiter, - struct rt_mutex *lock); -extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter); static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter, enum rtmutex_chainwalk walk) { return (waiter != NULL); } - -static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w) -{ - debug_rt_mutex_print_deadlock(w); -} diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 11abc60..4beca54 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -579,7 +579,6 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, * walk, we detected a deadlock. */ if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { - debug_rt_mutex_deadlock(chwalk, orig_waiter, lock); raw_spin_unlock(&lock->wait_lock); ret = -EDEADLK; goto out_unlock_pi; @@ -1171,8 +1170,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state, raw_spin_unlock_irq(&lock->wait_lock); - debug_rt_mutex_print_deadlock(waiter); - schedule(); raw_spin_lock_irq(&lock->wait_lock); @@ -1196,7 +1193,7 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock, /* * Yell loudly and stop the task right here. */ - rt_mutex_print_deadlock(w); + WARN(1, "rtmutex deadlock detected\n"); while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); @@ -1704,8 +1701,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock, ret = 0; } - debug_rt_mutex_print_deadlock(waiter); - return ret; } diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h index 4dbdec1..d77cb82 100644 --- a/kernel/locking/rtmutex.h +++ b/kernel/locking/rtmutex.h @@ -18,13 +18,6 @@ #define debug_rt_mutex_proxy_unlock(l) do { } while (0) #define debug_rt_mutex_unlock(l) do { } while (0) #define debug_rt_mutex_init(m, n, k) do { } while (0) -#define debug_rt_mutex_deadlock(d, a ,l) do { } while (0) -#define debug_rt_mutex_print_deadlock(w) do { } while (0) - -static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w) -{ - WARN(1, "rtmutex deadlock detected\n"); -} static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w, enum rtmutex_chainwalk walk) diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index aa04743..badb2a2 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -29,10 +29,6 @@ struct rt_mutex_waiter { struct rb_node pi_tree_entry; struct task_struct *task; struct rt_mutex *lock; -#ifdef CONFIG_DEBUG_RT_MUTEXES - struct pid *deadlock_task_pid; - struct rt_mutex *deadlock_lock; -#endif int prio; u64 deadline; };