From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 01/10] rcu: Mark accesses to boost_starttime
Date: Fri, 4 Feb 2022 15:23:57 -0800 [thread overview]
Message-ID: <20220204232406.814-1-paulmck@kernel.org> (raw)
In-Reply-To: <20220204232355.GA728@paulmck-ThinkPad-P17-Gen-1>
The boost_starttime shared variable has conflicting unmarked C-language
accesses, which are dangerous at best. This commit therefore adds
appropriate marking. This was found by KCSAN.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/rcutorture.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 422f7e4cc08de..829ae0b7d3c04 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -997,7 +997,7 @@ static int rcu_torture_boost(void *arg)
goto checkwait;
/* Wait for the next test interval. */
- oldstarttime = boost_starttime;
+ oldstarttime = READ_ONCE(boost_starttime);
while (time_before(jiffies, oldstarttime)) {
schedule_timeout_interruptible(oldstarttime - jiffies);
if (stutter_wait("rcu_torture_boost"))
@@ -1041,10 +1041,11 @@ static int rcu_torture_boost(void *arg)
* interval. Besides, we are running at RT priority,
* so delays should be relatively rare.
*/
- while (oldstarttime == boost_starttime && !kthread_should_stop()) {
+ while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
if (mutex_trylock(&boost_mutex)) {
if (oldstarttime == boost_starttime) {
- boost_starttime = jiffies + test_boost_interval * HZ;
+ WRITE_ONCE(boost_starttime,
+ jiffies + test_boost_interval * HZ);
n_rcu_torture_boosts++;
}
mutex_unlock(&boost_mutex);
--
2.31.1.189.g2e36527f23
next prev parent reply other threads:[~2022-02-04 23:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 23:23 [PATCH rcu 0/10] Real-time-related updates for v5.18 Paul E. McKenney
2022-02-04 23:23 ` Paul E. McKenney [this message]
2022-02-04 23:23 ` [PATCH rcu 02/10] rcu/nocb: Handle concurrent nocb kthreads creation Paul E. McKenney
2022-02-04 23:23 ` [PATCH rcu 03/10] rcu: Remove unused rcu_state.boost Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 04/10] rcu: Create per-cpu rcuc kthreads only when rcutree.use_softirq=0 Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 05/10] rcu: Move kthread_prio bounds-check to a separate function Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 06/10] rcu: Make priority of grace-period thread consistent Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 07/10] rcu: Elevate priority of offloaded callback threads Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 08/10] rcu: Update documentation regarding kthread_prio cmdline parameter Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 09/10] rcu: Don't deboost before reporting expedited quiescent state Paul E. McKenney
2022-02-04 23:24 ` [PATCH rcu 10/10] rcu: Add per-CPU rcuc task dumps to RCU CPU stall warnings Paul E. McKenney
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