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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 89471C7618F for ; Tue, 16 Jul 2019 18:30:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 698D020880 for ; Tue, 16 Jul 2019 18:30:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388393AbfGPSac (ORCPT ); Tue, 16 Jul 2019 14:30:32 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:9014 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725926AbfGPSac (ORCPT ); Tue, 16 Jul 2019 14:30:32 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x6GIM497023335; Tue, 16 Jul 2019 14:22:42 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tsjhm3684-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 Jul 2019 14:22:42 -0400 Received: from m0098410.ppops.net (m0098410.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x6GIMfN2024987; Tue, 16 Jul 2019 14:22:41 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tsjhm366p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 Jul 2019 14:22:41 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x6GIEnSN000902; Tue, 16 Jul 2019 18:22:39 GMT Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com [9.57.198.27]) by ppma01wdc.us.ibm.com with ESMTP id 2tq6x614my-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 Jul 2019 18:22:39 +0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x6GIMcsr49807648 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Jul 2019 18:22:38 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1EC40B206C; Tue, 16 Jul 2019 18:22:38 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AF59AB2067; Tue, 16 Jul 2019 18:22:37 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.80.225.134]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 16 Jul 2019 18:22:37 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id B6C1816C8F09; Tue, 16 Jul 2019 11:22:37 -0700 (PDT) Date: Tue, 16 Jul 2019 11:22:37 -0700 From: "Paul E. McKenney" To: "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org, Alexey Kuznetsov , Bjorn Helgaas , Borislav Petkov , c0d1n61at3@gmail.com, "David S. Miller" , edumazet@google.com, Greg Kroah-Hartman , Hideaki YOSHIFUJI , "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Josh Triplett , keescook@chromium.org, kernel-hardening@lists.openwall.com, kernel-team@android.com, Lai Jiangshan , Len Brown , linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Mathieu Desnoyers , neilb@suse.com, netdev@vger.kernel.org, Oleg Nesterov , Pavel Machek , peterz@infradead.org, "Rafael J. Wysocki" , Rasmus Villemoes , rcu@vger.kernel.org, Steven Rostedt , Tejun Heo , Thomas Gleixner , will@kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH v2 2/9] rcu: Add support for consolidated-RCU reader checking Message-ID: <20190716182237.GA22819@linux.ibm.com> Reply-To: paulmck@linux.ibm.com References: <20190712170024.111093-1-joel@joelfernandes.org> <20190712170024.111093-3-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190712170024.111093-3-joel@joelfernandes.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-16_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907160225 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jul 12, 2019 at 01:00:17PM -0400, Joel Fernandes (Google) wrote: > This patch adds support for checking RCU reader sections in list > traversal macros. Optionally, if the list macro is called under SRCU or > other lock/mutex protection, then appropriate lockdep expressions can be > passed to make the checks pass. > > Existing list_for_each_entry_rcu() invocations don't need to pass the > optional fourth argument (cond) unless they are under some non-RCU > protection and needs to make lockdep check pass. > > Signed-off-by: Joel Fernandes (Google) If you fold in the checks for extra parameters, I will take this one and also 1/9. Thanx, Paul > --- > include/linux/rculist.h | 28 +++++++++++++++++++++++----- > include/linux/rcupdate.h | 7 +++++++ > kernel/rcu/Kconfig.debug | 11 +++++++++++ > kernel/rcu/update.c | 14 ++++++++++++++ > 4 files changed, 55 insertions(+), 5 deletions(-) > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h > index e91ec9ddcd30..1048160625bb 100644 > --- a/include/linux/rculist.h > +++ b/include/linux/rculist.h > @@ -40,6 +40,20 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) > */ > #define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) > > +/* > + * Check during list traversal that we are within an RCU reader > + */ > + > +#ifdef CONFIG_PROVE_RCU_LIST > +#define __list_check_rcu(dummy, cond, ...) \ > + ({ \ > + RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \ > + "RCU-list traversed in non-reader section!"); \ > + }) > +#else > +#define __list_check_rcu(dummy, cond, ...) ({}) > +#endif > + > /* > * Insert a new entry between two known consecutive entries. > * > @@ -343,14 +357,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, > * @pos: the type * to use as a loop cursor. > * @head: the head for your list. > * @member: the name of the list_head within the struct. > + * @cond: optional lockdep expression if called from non-RCU protection. > * > * This list-traversal primitive may safely run concurrently with > * the _rcu list-mutation primitives such as list_add_rcu() > * as long as the traversal is guarded by rcu_read_lock(). > */ > -#define list_for_each_entry_rcu(pos, head, member) \ > - for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \ > - &pos->member != (head); \ > +#define list_for_each_entry_rcu(pos, head, member, cond...) \ > + for (__list_check_rcu(dummy, ## cond, 0), \ > + pos = list_entry_rcu((head)->next, typeof(*pos), member); \ > + &pos->member != (head); \ > pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) > > /** > @@ -616,13 +632,15 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n, > * @pos: the type * to use as a loop cursor. > * @head: the head for your list. > * @member: the name of the hlist_node within the struct. > + * @cond: optional lockdep expression if called from non-RCU protection. > * > * This list-traversal primitive may safely run concurrently with > * the _rcu list-mutation primitives such as hlist_add_head_rcu() > * as long as the traversal is guarded by rcu_read_lock(). > */ > -#define hlist_for_each_entry_rcu(pos, head, member) \ > - for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ > +#define hlist_for_each_entry_rcu(pos, head, member, cond...) \ > + for (__list_check_rcu(dummy, ## cond, 0), \ > + pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ > typeof(*(pos)), member); \ > pos; \ > pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index 922bb6848813..712b464ab960 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -223,6 +223,7 @@ int debug_lockdep_rcu_enabled(void); > int rcu_read_lock_held(void); > int rcu_read_lock_bh_held(void); > int rcu_read_lock_sched_held(void); > +int rcu_read_lock_any_held(void); > > #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > @@ -243,6 +244,12 @@ static inline int rcu_read_lock_sched_held(void) > { > return !preemptible(); > } > + > +static inline int rcu_read_lock_any_held(void) > +{ > + return !preemptible(); > +} > + > #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > #ifdef CONFIG_PROVE_RCU > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug > index 0ec7d1d33a14..b20d0e2903d1 100644 > --- a/kernel/rcu/Kconfig.debug > +++ b/kernel/rcu/Kconfig.debug > @@ -7,6 +7,17 @@ menu "RCU Debugging" > config PROVE_RCU > def_bool PROVE_LOCKING > > +config PROVE_RCU_LIST > + bool "RCU list lockdep debugging" > + depends on PROVE_RCU > + default n > + help > + Enable RCU lockdep checking for list usages. By default it is > + turned off since there are several list RCU users that still > + need to be converted to pass a lockdep expression. To prevent > + false-positive splats, we keep it default disabled but once all > + users are converted, we can remove this config option. > + > config TORTURE_TEST > tristate > default n > diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c > index bb961cd89e76..0cc7be0fb6b5 100644 > --- a/kernel/rcu/update.c > +++ b/kernel/rcu/update.c > @@ -294,6 +294,20 @@ int rcu_read_lock_bh_held(void) > } > EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); > > +int rcu_read_lock_any_held(void) > +{ > + if (!debug_lockdep_rcu_enabled()) > + return 1; > + if (!rcu_is_watching()) > + return 0; > + if (!rcu_lockdep_current_cpu_online()) > + return 0; > + if (lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_sched_lock_map)) > + return 1; > + return !preemptible(); > +} > +EXPORT_SYMBOL_GPL(rcu_read_lock_any_held); > + > #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > /** > -- > 2.22.0.510.g264f2c817a-goog >