From patchwork Mon Jul 15 14:36:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 11044357 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C723A6C5 for ; Mon, 15 Jul 2019 14:37:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B64DA205F8 for ; Mon, 15 Jul 2019 14:37:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A91CF205FD; Mon, 15 Jul 2019 14:37:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 6E1BA205F8 for ; Mon, 15 Jul 2019 14:37:43 +0000 (UTC) Received: (qmail 27829 invoked by uid 550); 15 Jul 2019 14:37:35 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 27720 invoked from network); 15 Jul 2019 14:37:34 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=CJEwPPrtJyDTV3piEkDE+ONyRMH9m2RDRbmoV5ZEGS8=; b=IozIr9z+GIb5mPdKiPaf5UHiYIz+Oat0gqj58xKeNgOqIcav4VXtm41dS18QhgHWuP 08bOfzHsvFlkA1+slmz0mYgCQced6RM3EOenJJaGW8k4oiXykx/eoqvUaynExjS780ga gIRPex9R8tFcEqFj6fn/uCxhibShb2XLfLQao= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=CJEwPPrtJyDTV3piEkDE+ONyRMH9m2RDRbmoV5ZEGS8=; b=J8OrAImcU7MCYQLwInG4hWVWu7bpP9usKupZQWl17z85ssWvBU1cMTyD5e/Jz4Nosc iy2JWC4VEMX9DiRptNMD2WXvdZGkcC24uvUPZKQ9EWc51/4lkTSz1tz7TW8VAyXzlUgh 6oEx4uR/f9wOS7ZnwzvK+sdlcn9S7Ih8j7E/PvNajXV5hC3Ldf0cir+eQ6CGDMDvOeID 5hFNfuTDJQfVA+C0biRbtrzDf+6cFFUywrO5PtMW18XZlAZjCD9lxugMgYq04AF+5d3X GyaJIpmECipzl0SxCysWj5Uvk6hE3OUTmPq4/ZkHpN4VMmGMcDV6l/hgR2AdGY1ooM6z SiPw== X-Gm-Message-State: APjAAAUnOAfAaQGV5mk1OmXclESro/AXqBqr9NUgu/vt7nTiBYkorTho LZjxXVewopfjZb4m4fU0GVM= X-Google-Smtp-Source: APXvYqzrTtDshfHRTIApwfR2uw8rmwlBdmV5rfV/lQ/WFFtfVs/RxHxaLHWVf+yG1vS25zf50JO+qA== X-Received: by 2002:a17:902:290b:: with SMTP id g11mr28300017plb.26.1563201442188; Mon, 15 Jul 2019 07:37:22 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , 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 , "Paul E. McKenney" , Pavel Machek , peterz@infradead.org, "Rafael J. Wysocki" , Rasmus Villemoes , rcu@vger.kernel.org, Steven Rostedt , Tejun Heo , Thomas Gleixner , will@kernel.org, x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)) Subject: [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3) Date: Mon, 15 Jul 2019 10:36:58 -0400 Message-Id: <20190715143705.117908-3-joel@joelfernandes.org> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog In-Reply-To: <20190715143705.117908-1-joel@joelfernandes.org> References: <20190715143705.117908-1-joel@joelfernandes.org> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP 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) --- include/linux/rculist.h | 28 ++++++++++++++++++++----- include/linux/rcupdate.h | 7 +++++++ kernel/rcu/Kconfig.debug | 11 ++++++++++ kernel/rcu/update.c | 44 ++++++++++++++++++++++++---------------- 4 files changed, 67 insertions(+), 23 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 8f7167478c1d..f3c29efdf19a 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -221,6 +221,7 @@ 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 */ @@ -241,6 +242,12 @@ 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 5ec3ea4028e2..7fbd21dbfcd0 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -8,6 +8,17 @@ 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 9dd5aeef6e70..b7a4e3b5fa98 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -91,14 +91,18 @@ module_param(rcu_normal_after_boot, int, 0); * Similarly, we avoid claiming an SRCU read lock held if the current * CPU is offline. */ +#define rcu_read_lock_held_common() \ + if (!debug_lockdep_rcu_enabled()) \ + return 1; \ + if (!rcu_is_watching()) \ + return 0; \ + if (!rcu_lockdep_current_cpu_online()) \ + return 0; + int rcu_read_lock_sched_held(void) { - if (!debug_lockdep_rcu_enabled()) - return 1; - if (!rcu_is_watching()) - return 0; - if (!rcu_lockdep_current_cpu_online()) - return 0; + rcu_read_lock_held_common(); + return lock_is_held(&rcu_sched_lock_map) || !preemptible(); } EXPORT_SYMBOL(rcu_read_lock_sched_held); @@ -257,12 +261,8 @@ NOKPROBE_SYMBOL(debug_lockdep_rcu_enabled); */ int rcu_read_lock_held(void) { - if (!debug_lockdep_rcu_enabled()) - return 1; - if (!rcu_is_watching()) - return 0; - if (!rcu_lockdep_current_cpu_online()) - return 0; + rcu_read_lock_held_common(); + return lock_is_held(&rcu_lock_map); } EXPORT_SYMBOL_GPL(rcu_read_lock_held); @@ -284,16 +284,24 @@ EXPORT_SYMBOL_GPL(rcu_read_lock_held); */ int rcu_read_lock_bh_held(void) { - if (!debug_lockdep_rcu_enabled()) - return 1; - if (!rcu_is_watching()) - return 0; - if (!rcu_lockdep_current_cpu_online()) - return 0; + rcu_read_lock_held_common(); + return in_softirq() || irqs_disabled(); } EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); +int rcu_read_lock_any_held(void) +{ + rcu_read_lock_held_common(); + + if (lock_is_held(&rcu_lock_map) || + lock_is_held(&rcu_bh_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 */ /**