From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 740D66B0315 for ; Wed, 24 May 2017 05:00:55 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id q27so5508110pfi.8 for ; Wed, 24 May 2017 02:00:55 -0700 (PDT) Received: from lgeamrelo11.lge.com (LGEAMRELO11.lge.com. [156.147.23.51]) by mx.google.com with ESMTP id c66si14473505pfj.90.2017.05.24.02.00.53 for ; Wed, 24 May 2017 02:00:54 -0700 (PDT) From: Byungchul Park Subject: [PATCH v7 10/16] lockdep: Make print_circular_bug() aware of crossrelease Date: Wed, 24 May 2017 17:59:43 +0900 Message-Id: <1495616389-29772-11-git-send-email-byungchul.park@lge.com> In-Reply-To: <1495616389-29772-1-git-send-email-byungchul.park@lge.com> References: <1495616389-29772-1-git-send-email-byungchul.park@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: peterz@infradead.org, mingo@kernel.org Cc: tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org, npiggin@gmail.com, kernel-team@lge.com print_circular_bug() reporting circular bug assumes that target hlock is owned by the current. However, in crossrelease, target hlock can be owned by other than the current. So the report format needs to be changed to reflect the change. Signed-off-by: Byungchul Park --- kernel/locking/lockdep.c | 65 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 45 insertions(+), 20 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 8173c81..45e9019 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1125,22 +1125,41 @@ static inline int __bfs_backwards(struct lock_list *src_entry, printk(KERN_CONT "\n\n"); } - printk(" Possible unsafe locking scenario:\n\n"); - printk(" CPU0 CPU1\n"); - printk(" ---- ----\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(parent); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(source); - printk(KERN_CONT ");\n"); - printk("\n *** DEADLOCK ***\n\n"); + if (cross_lock(tgt->instance)) { + printk(" Possible unsafe locking scenario by crosslock:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(parent); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(source); + printk(KERN_CONT ");\n"); + printk(" unlock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk("\n *** DEADLOCK ***\n\n"); + } else { + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(parent); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(source); + printk(KERN_CONT ");\n"); + printk("\n *** DEADLOCK ***\n\n"); + } } /* @@ -1165,7 +1184,10 @@ static inline int __bfs_backwards(struct lock_list *src_entry, printk("%s/%d is trying to acquire lock:\n", curr->comm, task_pid_nr(curr)); print_lock(check_src); - printk("\nbut task is already holding lock:\n"); + if (cross_lock(check_tgt->instance)) + printk("\nbut now in release context of a crosslock acquired at the following:\n"); + else + printk("\nbut task is already holding lock:\n"); print_lock(check_tgt); printk("\nwhich lock already depends on the new lock.\n\n"); printk("\nthe existing dependency chain (in reverse order) is:\n"); @@ -1183,7 +1205,8 @@ static inline int class_equal(struct lock_list *entry, void *data) static noinline int print_circular_bug(struct lock_list *this, struct lock_list *target, struct held_lock *check_src, - struct held_lock *check_tgt) + struct held_lock *check_tgt, + struct stack_trace *trace) { struct task_struct *curr = current; struct lock_list *parent; @@ -1193,7 +1216,9 @@ static noinline int print_circular_bug(struct lock_list *this, if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; - if (!save_trace(&this->trace)) + if (cross_lock(check_tgt->instance)) + this->trace = *trace; + else if (!save_trace(&this->trace)) return 0; depth = get_lock_depth(target); @@ -1837,7 +1862,7 @@ static inline void inc_chains(void) this.parent = NULL; ret = check_noncircular(&this, hlock_class(prev), &target_entry); if (unlikely(!ret)) - return print_circular_bug(&this, target_entry, next, prev); + return print_circular_bug(&this, target_entry, next, prev, trace); else if (unlikely(ret < 0)) return print_bfs_bug(ret); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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