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=-8.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 BE87DC43444 for ; Wed, 9 Jan 2019 21:04:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80530206B7 for ; Wed, 9 Jan 2019 21:04:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=mailprotect.be header.i=@mailprotect.be header.b="m9egRaot" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728002AbfAIVED (ORCPT ); Wed, 9 Jan 2019 16:04:03 -0500 Received: from out002.mailprotect.be ([83.217.72.86]:60897 "EHLO out002.mailprotect.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726581AbfAIVCz (ORCPT ); Wed, 9 Jan 2019 16:02:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mailprotect.be; s=mail; h=Content-Transfer-Encoding:MIME-Version:References :In-Reply-To:Message-Id:Date:Subject:Cc:To:From:reply-to:sender:bcc: content-type; bh=PghefKGP1xLj4fm0v32hMCl3oD4uxTLWTkiRCXFqYyY=; b=m9egRaotRHB+ mugxL09ZWUTFML0Xh/qZ51pQsrj6Xg1IkBmOZWTkD8f24OmPfeApPkKdIq/TAD6XL2pV4SzG17L5F Zn3pOdRTUI3bRYsfOXy8LO2zpZdmztqJqrTyPHqyz4r0aFZ1t4amLrtTh1RgtQioZNt40fiQA52eL EYhfO1CmS2b5LLYZUDwfT1KJJobAj410B/JsqgMOvpfuECuP3WWVFWBEwYWMJQhiAECTE8ffUoUCu bmAhllXmdKFsxgVc6hVj4UMVL3lJ4/9TQBacfeRGGaqZg0wvNGn3qePhtQg4Tbn0cxItDwZTwvxRU Vh2zG4KcXzzt1jzuOKMLKA==; Received: from smtp-auth.mailprotect.be ([178.208.39.159]) by com-mpt-out002.mailprotect.be with esmtp (Exim 4.89) (envelope-from ) id 1ghKzt-0009Cr-3i; Wed, 09 Jan 2019 22:02:45 +0100 Received: from desktop-bart.svl.corp.google.com (unknown [104.133.8.89]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp-auth.mailprotect.be (Postfix) with ESMTPSA id 34A1AC15F1; Wed, 9 Jan 2019 22:02:40 +0100 (CET) From: Bart Van Assche To: peterz@infradead.org Cc: mingo@redhat.com, tj@kernel.org, longman@redhat.com, johannes.berg@intel.com, linux-kernel@vger.kernel.org, Bart Van Assche , Johannes Berg Subject: [PATCH v6 11/16] locking/lockdep: Reuse lock chains that have been freed Date: Wed, 9 Jan 2019 13:01:59 -0800 Message-Id: <20190109210204.192109-12-bvanassche@acm.org> X-Mailer: git-send-email 2.20.1.97.g81188d93c3-goog In-Reply-To: <20190109210204.192109-1-bvanassche@acm.org> References: <20190109210204.192109-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Originating-IP: 178.208.39.159 X-SpamExperts-Domain: mailprotect.be X-SpamExperts-Username: 178.208.39.128/27 Authentication-Results: mailprotect.be; auth=pass smtp.auth=178.208.39.128/27@mailprotect.be X-SpamExperts-Outgoing-Class: ham X-SpamExperts-Outgoing-Evidence: SB/global_tokens (0.00494465996194) X-Recommended-Action: accept X-Filter-ID: EX5BVjFpneJeBchSMxfU5uqedaKDPRmr6hTD/1wcFW1602E9L7XzfQH6nu9C/Fh9KJzpNe6xgvOx q3u0UDjvO1tLifGj39bI0bcPyaJsYTb/+zriNZuqQk0xRpGwjn+MTR8dtByWYYhgj25jR+mEA3YO AtfhCcV13BpIh8lqRXSSiFVwqwU9VgKUrYQ0lqWyFDaym8oavoPYsm7m1mVEGf0/5ST3nkt5XYDK YAuRpmF7E2F3eqKXiTd2ECUghryWXlqwG31yUGf3t09vBVYS71V1Pk0aHudBU1wyWVTA5OYS1waI XXCBiQFDV0yen8nGcSeERs4TOTnIH1kc1IWc5eLazqbUYkjl7F1LyK0RORphPu8jd2ydSlJFjq08 CAcGSNgvEAWLFiDAlQR6Wu0I/iWDegq4fQ11AxLVlrI7DVH6GzPz+r852EXXeYX4ImMyzDg6HYuT CyYgL61SIkBTYXPEvhymCNb22qmKERGbL1SqvGGff0htQqhQf0/aDrhpLM4xnCPpmyyS7jgD9Nen VVoB/PLX+rmdznc91veCJAwpCI+5VHpzDqRcT2+GtIE8SRAgmLDKAcp9i+Q+BEiSUj07SNjVkl0P Pj+OUYZX3/3Z86X+I1ED1LLv7p/g4HOOdbYb9IXfYGRpVS/0hA4Mwp9kB6JZdl+SJy+nWImyKEy/ zJE11ZjKQFiKV8EwnkodMjMm/D2rEPnNAuCCnt9B91Ax/uigYcgpQGDKFCrOdd8gr/U0flMcy2Vi /IcBgY4aVBKUAPQbBk8nfWT8Lcjyyn9ZSA9YgSwQmLSJwsFnO3lUxpF8dVvwCXY/4mE1q/c/E53d gi3vLmcjfrrMypRHn7OOqpiCgGRKllFsZ2U4mg8UK6YK/Z3Z4VqycLjuCh+BX1KrFIDnIhhlHDLh vRwgYpikjrjEsQHYqzPksYepQjQSeP/rn+UB/EmrduGPxHj/dKsQ+WcgzL7pTOYRE2yEvlBrMyfp YuyanAZpMXssfrVwLrD8rqLg0SqQCDr4y/2aQSUN8kFnhD7o+VyQ1oD3roKXmjBL5uwLhkPo1jOY 3CLYhBKQrXFod+WvUUP1Uys1SCu8wQmWlqgUhZKbKdwa/OuO5TcDeKjrEmYPn2IVWRtfdRHps2br TOkutpvyrdmtvbYO9ASW9x0dzW2b+IEXgSV5FVT0nNNOs1IDBtijAxf8XG910biZEcomWehz4u8s zDg6HYuTCyYgL61SIkBTYSiCBqrB4vMmHpjmx6wTDBzk2EPy497nssgnoMkIb3rMdj8luXC7km26 QtXP9s02LA== X-Report-Abuse-To: spam@com-mpt-mgt001.mailprotect.be Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A previous patch introduced a lock chain leak. Fix that leak by reusing lock chains that have been freed. Cc: Peter Zijlstra Cc: Waiman Long Cc: Johannes Berg Signed-off-by: Bart Van Assche --- kernel/locking/lockdep.c | 62 ++++++++++++++++++++++------------------ 1 file changed, 34 insertions(+), 28 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index ef3809e21fa9..a8ea03bfc944 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -299,6 +299,7 @@ static struct pending_free { struct rcu_head rcu_head; bool scheduled; DECLARE_BITMAP(list_entries_being_freed, MAX_LOCKDEP_ENTRIES); + DECLARE_BITMAP(lock_chains_being_freed, MAX_LOCKDEP_CHAINS); } pending_free[2]; static DECLARE_WAIT_QUEUE_HEAD(rcu_cb); @@ -2110,8 +2111,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) return 0; } -static unsigned long nr_lock_chains; struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; +static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS); int nr_chain_hlocks; static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; @@ -2250,12 +2251,25 @@ static int check_no_collision(struct task_struct *curr, */ long lockdep_next_lockchain(long i) { - return i + 1 < nr_lock_chains ? i + 1 : -2; + i = find_next_bit(lock_chains_in_use, ARRAY_SIZE(lock_chains), i + 1); + return i < ARRAY_SIZE(lock_chains) ? i : -2; } unsigned long lock_chain_count(void) { - return nr_lock_chains; + return bitmap_weight(lock_chains_in_use, ARRAY_SIZE(lock_chains)); +} + +/* Must be called with the graph lock held. */ +static struct lock_chain *alloc_lock_chain(void) +{ + int idx = find_first_zero_bit(lock_chains_in_use, + ARRAY_SIZE(lock_chains)); + + if (unlikely(idx >= ARRAY_SIZE(lock_chains))) + return NULL; + __set_bit(idx, lock_chains_in_use); + return lock_chains + idx; } /* @@ -2274,20 +2288,8 @@ static inline int add_chain_cache(struct task_struct *curr, struct lock_chain *chain; int i, j; - /* - * Allocate a new chain entry from the static array, and add - * it to the hash: - */ - - /* - * We might need to take the graph lock, ensure we've got IRQs - * disabled to make this an IRQ-safe lock.. for recursion reasons - * lockdep won't complain about its own locking errors. - */ - if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) - return 0; - - if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { + chain = alloc_lock_chain(); + if (!chain) { if (!debug_locks_off_graph_unlock()) return 0; @@ -2295,7 +2297,6 @@ static inline int add_chain_cache(struct task_struct *curr, dump_stack(); return 0; } - chain = lock_chains + nr_lock_chains++; chain->chain_key = chain_key; chain->irq_context = hlock->irq_context; i = get_first_held_lock(curr, hlock); @@ -4223,7 +4224,8 @@ void lockdep_reset(void) } /* Remove a class from a lock chain. Must be called with the graph lock held. */ -static void remove_class_from_lock_chain(struct lock_chain *chain, +static void remove_class_from_lock_chain(struct pending_free *pf, + struct lock_chain *chain, struct lock_class *class) { #ifdef CONFIG_PROVE_LOCKING @@ -4261,6 +4263,7 @@ static void remove_class_from_lock_chain(struct lock_chain *chain, * hlist_for_each_entry_rcu() loop is safe. */ hlist_del_rcu(&chain->entry); + __set_bit(chain - lock_chains, pf->lock_chains_being_freed); if (chain->depth == 0) return; /* @@ -4269,22 +4272,19 @@ static void remove_class_from_lock_chain(struct lock_chain *chain, */ if (lookup_chain_cache(chain_key)) return; - if (WARN_ON_ONCE(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { + new_chain = alloc_lock_chain(); + if (WARN_ON_ONCE(!new_chain)) { debug_locks_off(); return; } - /* - * Leak *chain because it is not safe to reinsert it before an RCU - * grace period has expired. - */ - new_chain = lock_chains + nr_lock_chains++; *new_chain = *chain; hlist_add_head_rcu(&new_chain->entry, chainhashentry(chain_key)); #endif } /* Must be called with the graph lock held. */ -static void remove_class_from_lock_chains(struct lock_class *class) +static void remove_class_from_lock_chains(struct pending_free *pf, + struct lock_class *class) { struct lock_chain *chain; struct hlist_head *head; @@ -4293,7 +4293,7 @@ static void remove_class_from_lock_chains(struct lock_class *class) for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) { head = chainhash_table + i; hlist_for_each_entry_rcu(chain, head, entry) { - remove_class_from_lock_chain(chain, class); + remove_class_from_lock_chain(pf, chain, class); } } } @@ -4334,7 +4334,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class) class->name); } - remove_class_from_lock_chains(class); + remove_class_from_lock_chains(pf, class); } static void reinit_class(struct lock_class *class) @@ -4383,6 +4383,11 @@ static void free_zapped_classes(struct rcu_head *ch) bitmap_andnot(list_entries_in_use, list_entries_in_use, pf->list_entries_being_freed, ARRAY_SIZE(list_entries)); bitmap_clear(pf->list_entries_being_freed, 0, ARRAY_SIZE(list_entries)); +#ifdef CONFIG_PROVE_LOCKING + bitmap_andnot(lock_chains_in_use, lock_chains_in_use, + pf->lock_chains_being_freed, ARRAY_SIZE(lock_chains)); + bitmap_clear(pf->lock_chains_being_freed, 0, ARRAY_SIZE(lock_chains)); +#endif graph_unlock(); restore_irqs: raw_local_irq_restore(flags); @@ -4675,6 +4680,7 @@ void __init lockdep_init(void) #ifdef CONFIG_PROVE_LOCKING + sizeof(lock_cq) + sizeof(lock_chains) + + sizeof(lock_chains_in_use) + sizeof(chain_hlocks) #endif ) / 1024 -- 2.20.1.97.g81188d93c3-goog