From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751959AbeCIBKd (ORCPT ); Thu, 8 Mar 2018 20:10:33 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60040 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751205AbeCIBKc (ORCPT ); Thu, 8 Mar 2018 20:10:32 -0500 Date: Thu, 8 Mar 2018 17:01:00 -0800 From: "Paul E. McKenney" To: Boqun Feng Cc: kbuild test robot , kbuild-all@01.org, linux-kernel@vger.kernel.org Subject: Re: [rcu:rcu/dev 39/39] kernel/rcu/tree_exp.h:163:9: sparse: incorrect type in argument 1 (different modifiers) Reply-To: paulmck@linux.vnet.ibm.com References: <201803090524.gbCGY9DF%fengguang.wu@intel.com> <20180308225234.v2v6v5tnfkutwu5u@tardis> <20180309003443.GX3918@linux.vnet.ibm.com> <20180309005154.ujapyqqzmwafuo5t@tardis> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180309005154.ujapyqqzmwafuo5t@tardis> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18030901-0056-0000-0000-0000042AB27A X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008637; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000254; SDB=6.01000281; UDB=6.00508782; IPR=6.00779611; MB=3.00019924; MTD=3.00000008; XFM=3.00000015; UTC=2018-03-09 01:00:25 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030901-0057-0000-0000-0000086CB944 Message-Id: <20180309010100.GB3918@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-08_14:,, 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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803090012 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 09, 2018 at 08:51:54AM +0800, Boqun Feng wrote: > On Thu, Mar 08, 2018 at 04:34:43PM -0800, Paul E. McKenney wrote: > > On Fri, Mar 09, 2018 at 06:52:34AM +0800, Boqun Feng wrote: > > > On Fri, Mar 09, 2018 at 05:41:27AM +0800, kbuild test robot wrote: > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/dev > > > > head: b8909ec707bb5beba94e7c7d62cc6b3115ceae50 > > > > commit: b8909ec707bb5beba94e7c7d62cc6b3115ceae50 [39/39] rcu: Protect all sync_rcu_preempt_exp_done() with rcu_node lock > > > > reproduce: > > > > # apt-get install sparse > > > > git checkout b8909ec707bb5beba94e7c7d62cc6b3115ceae50 > > > > make ARCH=x86_64 allmodconfig > > > > make C=1 CF=-D__CHECK_ENDIAN__ > > > > > > > > > > > > sparse warnings: (new ones prefixed by >>) > > > > > > > [...] > > > > kernel/rcu/tree.c:345:6: sparse: symbol 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static? > > > > kernel/rcu/tree.c:3953:21: sparse: incorrect type in argument 1 (different modifiers) @@ expected int ( *threadfn )( ... ) @@ got int ( [noreint ( *threadfn )( ... ) @@ > > > > kernel/rcu/tree.c:3953:21: expected int ( *threadfn )( ... ) > > > > kernel/rcu/tree.c:3953:21: got int ( [noreturn] * )( ... ) > > > > >> kernel/rcu/tree_exp.h:163:9: sparse: incorrect type in argument 1 (different modifiers) @@ expected struct lockdep_map const *lock @@ got strustruct lockdep_map const *lock @@ > > > > kernel/rcu/tree_exp.h:163:9: expected struct lockdep_map const *lock > > > > kernel/rcu/tree_exp.h:163:9: got struct lockdep_map [noderef] * > > > > kernel/rcu/tree.c:1752:9: sparse: context imbalance in 'rcu_start_future_gp' - different lock contexts for basic block > > > > kernel/rcu/tree.c:2786:9: sparse: context imbalance in 'force_qs_rnp' - different lock contexts for basic block > > > > kernel/rcu/tree.c:2849:25: sparse: context imbalance in 'force_quiescent_state' - unexpected unlock > > > > kernel/rcu/tree_exp.h:203:9: sparse: too many warnings > > > > > > > > vim +163 kernel/rcu/tree_exp.h > > > > > > > > 151 > > > > 152 /* > > > > 153 * Return non-zero if there is no RCU expedited grace period in progress > > > > 154 * for the specified rcu_node structure, in other words, if all CPUs and > > > > 155 * tasks covered by the specified rcu_node structure have done their bit > > > > 156 * for the current expedited grace period. Works only for preemptible > > > > 157 * RCU -- other RCU implementation use other means. > > > > 158 * > > > > 159 * Caller must hold the specificed rcu_node structure's ->lock > > > > 160 */ > > > > 161 static bool sync_rcu_preempt_exp_done(struct rcu_node *rnp) > > > > 162 { > > > > > 163 lockdep_assert_held(&rnp->lock); > > > > > > OK, so we need ACCESS_PRIVATE() to visit ->lock in rcu_node. I will > > > introduce something like: > > > > > > #define rcu_node_lock_assert_held(rnp) lockdep_assert_held(&ACCESS_PRIVATE(rnp, lock)) > > > > > > in v3. > > > > Or use this, which is in kernel/rcu/rcu.h: > > > > #define raw_lockdep_assert_held_rcu_node(p) \ > > lockdep_assert_held(&ACCESS_PRIVATE(p, lock)) > > Good point, thank you for pointing this out ;-) "It is a service that I provide." ;-) I removed your earlier patch in anticipation of the next version. Thanx, Paul