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From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	mingo@kernel.org, jiangshanlai@gmail.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" <paulmck@kernel.org>
Subject: [PATCH rcu 7/7] scftorture: Avoid NULL pointer exception on early exit
Date: Wed, 21 Jul 2021 14:04:41 -0700	[thread overview]
Message-ID: <20210721210441.796995-7-paulmck@kernel.org> (raw)
In-Reply-To: <20210721210421.GA788053@paulmck-ThinkPad-P17-Gen-1>

When scftorture finds an error in the module parameters controlling
the relative frequencies of smp_call_function*() variants, it takes an
early exit.  So early that it has not allocated memory to track the
kthreads running the test, which results in a segfault.  This commit
therefore checks for the existence of the memory before attempting
to stop the kthreads that would otherwise have been recorded in that
non-existent memory.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/scftorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/scftorture.c b/kernel/scftorture.c
index 5cf40e4383191..64a08288b1a6d 100644
--- a/kernel/scftorture.c
+++ b/kernel/scftorture.c
@@ -513,7 +513,7 @@ static void scf_torture_cleanup(void)
 		return;
 
 	WRITE_ONCE(scfdone, true);
-	if (nthreads)
+	if (nthreads && scf_stats_p)
 		for (i = 0; i < nthreads; i++)
 			torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
 	else
-- 
2.31.1.189.g2e36527f23


      parent reply	other threads:[~2021-07-21 21:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-21 21:04 [PATCH rcu 0/7] Torture-test updates for v5.15 Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 1/7] refscale: Add measurement of clock readout Paul E. McKenney
2021-07-28 17:38   ` [PATCH v2 " Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 2/7] rcutorture: Preempt rather than block when testing task stalls Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 3/7] rcuscale: Console output claims too few grace periods Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 4/7] locktorture: Mark statistics data races Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 5/7] locktorture: Count lock readers Paul E. McKenney
2021-07-21 21:04 ` [PATCH rcu 6/7] scftorture: Add RPC-like IPI tests Paul E. McKenney
2021-07-21 21:04 ` Paul E. McKenney [this message]

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