From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162424AbdEXJBI (ORCPT ); Wed, 24 May 2017 05:01:08 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:36773 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161589AbdEXJA5 (ORCPT ); Wed, 24 May 2017 05:00:57 -0400 X-Original-SENDERIP: 156.147.1.126 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park 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 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> X-Mailer: git-send-email 1.9.1 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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