From nobody Mon Feb 9 14:33:19 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=1584104845; cv=none; d=zohomail.com; s=zohoarc; b=XeKzyvwtlR+YRxkq6IUBNcMh7pAKAFC5GoiYrmHCl/0bwQiIioOJPJGKM/1QGHW9ezCSO+QLJsPyAnU4d1q4j+QYTlEt1w79ces3QvxdGKcJKHmqLFf+G2wkXE1xTjcHVxVhsm4bCF/G+ZTlzjEApH2IHFXhMTC+/EHv5pvkXmY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1584104845; 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=HF2sKh3fVXcXESEuyZ/F+cywtw9JIKMWmdxLajFoPpA=; b=XYMV/Ri/SeDi0XFQkLVkzInYAfQZZj4lMShPbezyx/BwEIvTGgYVewFWlwq7nyIfbHYOgNEpgZ2c1gAwnlNzTmnAjLK1+snHkdIJCcZ/Y+oBQCORBhT0EwTXNOhEzRJ8ObH/b3BJLIxXllOAkkVxI4Kdl+EmfyS4StklwICua0M= 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 1584104845069735.7126511574954; Fri, 13 Mar 2020 06:07:25 -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 1jCk1B-00019D-T6; Fri, 13 Mar 2020 13:06:25 +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 1jCk1A-00018w-5B for xen-devel@lists.xenproject.org; Fri, 13 Mar 2020 13:06:24 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 6c6a5ebd-652b-11ea-b2f0-12813bfff9fa; Fri, 13 Mar 2020 13:06:18 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 673FEAFCA; Fri, 13 Mar 2020 13:06:17 +0000 (UTC) X-Inumbo-ID: 6c6a5ebd-652b-11ea-b2f0-12813bfff9fa X-Virus-Scanned: by amavisd-new at test-mx.suse.de From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Fri, 13 Mar 2020 14:06:14 +0100 Message-Id: <20200313130614.27265-5-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200313130614.27265-1-jgross@suse.com> References: <20200313130614.27265-1-jgross@suse.com> Subject: [Xen-devel] [PATCH v6 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 Reviewed-by: Jan Beulich --- 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 d3c2b7b093..e0c3b16e7d 100644 --- a/xen/include/xen/rcupdate.h +++ b/xen/include/xen/rcupdate.h @@ -37,21 +37,50 @@ #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) { preempt_disable(); 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)--; preempt_enable(); } @@ -81,15 +110,6 @@ 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. * @@ -118,7 +138,7 @@ 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 /** @@ -129,7 +149,7 @@ 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