From nobody Tue Feb 10 03:44:43 2026 Delivered-To: importer@patchew.org Received-SPF: none (zohomail.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=none (zohomail.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1584001767; cv=none; d=zohomail.com; s=zohoarc; b=QdIeSIp3C/gyc0DSiYJ6it7raiBMM2T84+eCw+LRyp/XcE2Riy+IUdkOUhrmk5ewJm8CKO/G/oEhqBCUPZHXvVS/oKNlKAqfWNoecMQpIMHAdjS/DJlvCS9QOtgKS1Caqnpv27mvpXlv6QzpLuauXtnY9RDQ4e/ejSwOnH6rcTQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1584001767; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=QNmMkgHZtI+4EpNw+GemCgRYQG9ykz3AQ6uIPYEMqfA=; b=IM7oWQ2xeuuVGVO40ICNE6OS9t02JtnsgQhswrW1xkfWW2/ygQRUwQP5aaNilbdZ4igKKvpte8kVzaAsUWl/VNV8fzyJTY3uSYgIdI1sAFndeeAj8oOyIEU7AWupxifS69iPORyWvqD8F26cBLqmSti5oF15MY+NLYMBz/QJkF0= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=none (zohomail.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1584001767007707.0078534553803; Thu, 12 Mar 2020 01:29:27 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jCJCu-0004uK-Dm; Thu, 12 Mar 2020 08:28:44 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jCJCs-0004u0-RD for xen-devel@lists.xenproject.org; Thu, 12 Mar 2020 08:28:42 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 76d89566-643b-11ea-b127-12813bfff9fa; Thu, 12 Mar 2020 08:28:36 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 3401EB24A; Thu, 12 Mar 2020 08:28:35 +0000 (UTC) X-Inumbo-ID: 76d89566-643b-11ea-b127-12813bfff9fa X-Virus-Scanned: by amavisd-new at test-mx.suse.de From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Thu, 12 Mar 2020 09:28:31 +0100 Message-Id: <20200312082831.22280-5-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200312082831.22280-1-jgross@suse.com> References: <20200312082831.22280-1-jgross@suse.com> Subject: [Xen-devel] [PATCH v5 4/4] xen/rcu: add per-lock counter in debug builds X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , Julien Grall , Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , Jan Beulich MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Add a lock specific counter to rcu read locks in debug builds. This allows to test for matching lock/unlock calls. This will help to avoid cases like the one fixed by commit 98ed1f43cc2c89 where different rcu read locks were referenced in the lock and unlock calls. Signed-off-by: Juergen Gross --- V5: - updated commit message (Jan Beulich) --- xen/include/xen/rcupdate.h | 46 +++++++++++++++++++++++++++++++++---------= ---- 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/xen/include/xen/rcupdate.h b/xen/include/xen/rcupdate.h index be807694e7..3e9b0b180e 100644 --- a/xen/include/xen/rcupdate.h +++ b/xen/include/xen/rcupdate.h @@ -36,20 +36,49 @@ #include #include #include +#include =20 #define __rcu =20 +#ifndef NDEBUG +/* * Lock type for passing to rcu_read_{lock,unlock}. */ +struct _rcu_read_lock { + atomic_t cnt; +}; +typedef struct _rcu_read_lock rcu_read_lock_t; +#define DEFINE_RCU_READ_LOCK(x) rcu_read_lock_t x =3D { .cnt =3D ATOMIC_IN= IT(0) } +#define RCU_READ_LOCK_INIT(x) atomic_set(&(x)->cnt, 0) + +#else +/* + * Dummy lock type for passing to rcu_read_{lock,unlock}. Currently exists + * only to document the reason for rcu_read_lock() critical sections. + */ +struct _rcu_read_lock {}; +typedef struct _rcu_read_lock rcu_read_lock_t; +#define DEFINE_RCU_READ_LOCK(x) rcu_read_lock_t x +#define RCU_READ_LOCK_INIT(x) + +#endif + DECLARE_PER_CPU(unsigned int, rcu_lock_cnt); =20 -static inline void rcu_quiesce_disable(void) +static inline void rcu_quiesce_disable(rcu_read_lock_t *lock) { this_cpu(rcu_lock_cnt)++; +#ifndef NDEBUG + atomic_inc(&lock->cnt); +#endif barrier(); } =20 -static inline void rcu_quiesce_enable(void) +static inline void rcu_quiesce_enable(rcu_read_lock_t *lock) { barrier(); +#ifndef NDEBUG + ASSERT(atomic_read(&lock->cnt)); + atomic_dec(&lock->cnt); +#endif this_cpu(rcu_lock_cnt)--; } =20 @@ -78,15 +107,6 @@ struct rcu_head { int rcu_pending(int cpu); int rcu_needs_cpu(int cpu); =20 -/* - * Dummy lock type for passing to rcu_read_{lock,unlock}. Currently exists - * only to document the reason for rcu_read_lock() critical sections. - */ -struct _rcu_read_lock {}; -typedef struct _rcu_read_lock rcu_read_lock_t; -#define DEFINE_RCU_READ_LOCK(x) rcu_read_lock_t x -#define RCU_READ_LOCK_INIT(x) - /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. * @@ -115,7 +135,7 @@ typedef struct _rcu_read_lock rcu_read_lock_t; */ static inline void rcu_read_lock(rcu_read_lock_t *lock) { - rcu_quiesce_disable(); + rcu_quiesce_disable(lock); } =20 /** @@ -126,7 +146,7 @@ static inline void rcu_read_lock(rcu_read_lock_t *lock) static inline void rcu_read_unlock(rcu_read_lock_t *lock) { ASSERT(!rcu_quiesce_allowed()); - rcu_quiesce_enable(); + rcu_quiesce_enable(lock); } =20 /* --=20 2.16.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel