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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 1 Aug 2019 23:37:48 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x71Mbl6b52232640 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 1 Aug 2019 22:37:47 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6D1CAB2075; Thu, 1 Aug 2019 22:37:47 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4DF0AB2077; Thu, 1 Aug 2019 22:37:47 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.154]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 1 Aug 2019 22:37:47 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 5BBC216C9A4E; Thu, 1 Aug 2019 15:37:48 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 06/12] srcu: Avoid srcutorture security-based pointer obfuscation Date: Thu, 1 Aug 2019 15:37:41 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190801223708.GA14862@linux.ibm.com> References: <20190801223708.GA14862@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19080122-0060-0000-0000-0000036770D0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011535; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000287; SDB=6.01240734; UDB=6.00654294; IPR=6.01022158; MB=3.00028000; MTD=3.00000008; XFM=3.00000015; UTC=2019-08-01 22:37:52 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19080122-0061-0000-0000-00004A62765E Message-Id: <20190801223747.15560-6-paulmck@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-01_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=13 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=990 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908010238 Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Because pointer output is now obfuscated, and because what you really want to know is whether or not the callback lists are empty, this commit replaces the srcu_data structure's head callback pointer printout with a single character that is "." is the callback list is empty or "C" otherwise. This is the only remaining user of rcu_segcblist_head(), so this commit also removes this function's definition. It also turns out that rcu_segcblist_tail() no longer has any callers, so this commit removes that function's definition while in the area. They were both marked "Interim", and their end has come. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu_segcblist.h | 21 --------------------- kernel/rcu/srcutree.c | 5 +++-- 2 files changed, 3 insertions(+), 23 deletions(-) diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 71b64648464e..822a39da0533 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -76,27 +76,6 @@ static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg) return !*rsclp->tails[seg]; } -/* - * Interim function to return rcu_segcblist head pointer. Longer term, the - * rcu_segcblist will be used more pervasively, removing the need for this - * function. - */ -static inline struct rcu_head *rcu_segcblist_head(struct rcu_segcblist *rsclp) -{ - return rsclp->head; -} - -/* - * Interim function to return rcu_segcblist head pointer. Longer term, the - * rcu_segcblist will be used more pervasively, removing the need for this - * function. - */ -static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp) -{ - WARN_ON_ONCE(rcu_segcblist_empty(rsclp)); - return rsclp->tails[RCU_NEXT_TAIL]; -} - void rcu_segcblist_init(struct rcu_segcblist *rsclp); void rcu_segcblist_disable(struct rcu_segcblist *rsclp); bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp); diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index cf0e886314f2..5dffade2d7cd 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1279,8 +1279,9 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf) c0 = l0 - u0; c1 = l1 - u1; - pr_cont(" %d(%ld,%ld %1p)", - cpu, c0, c1, rcu_segcblist_head(&sdp->srcu_cblist)); + pr_cont(" %d(%ld,%ld %c)", + cpu, c0, c1, + "C."[rcu_segcblist_empty(&sdp->srcu_cblist)]); s0 += c0; s1 += c1; } -- 2.17.1